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Reclassifying the nonmetals[edit]

Reclassifying the nonmetals is the title of an original post here at WT:ELEMENTS by Sandbh, 12 March 2017. Long and large discussions followed, now in the archives. Below is the current status. -DePiep (talk) 22:30, 27 July 2017 (UTC)

Open (not archived yet)
(do not archive timestamp) -DePiep (talk) 21:18, 15 November 2017 (UTC)

Long post re (gasp!) other nonmetals[edit]

I never found this section title sympathic or fine, but I can understand Sandbh's first response. (Is why I kept the original title). Below, I opened a new ==-level section with a more neutral title. -DePiep (talk) 00:19, 8 November 2017 (UTC)

Now what to do with the 'other nonmetals'?[edit]

Initial post by Sandbh[edit]

Posted here for project members rather than the broader RfC audience.

Colleagues, my impression at this point, and subject to your views, is that the RfC should be closed due to consensus not being obtained.

I’ve thought long and hard about what happens next.

I now propose, as per @R8R:’s preference, that we have only two categories of nonmetal:

(1) a placeholder category of "other nonmetal"; and
(2) a noble gas category.

Yikes! Not other nonmetals again! I know, I know: please read the rest of my post carefully before making a judgment about this term.

Importantly, this proposal is consistent with (a) the example given by EvilXFish, i.e. which is the top rated Google result, and (b) the Encyclopedia Britannica. I also recall that all project members apart from me were happy with a single non-noble gas nonmetal category.

In our colour category table the name other nonmetal would be used only to avoid the need for a more cumbersome collective term such as "non-noble nonmetals", or "nonmetals other than noble gases", given there is no widely-used proper alternative category name, including "chemically active nonmetals", which is the point made by those who opposed my original proposal.

Since "other nonmetal" is a placeholder name rather than a proper taxonomic category name, there is no real further need for its use in the singular. For example, chemists usually refer to group 14 as comprising carbon, a nonmetal; silicon and germanium, metalloids; and tin and lead as metals. The fact that lead is a post-transition metal is convenient when discussing this particular category of metals as a whole but it is otherwise not usually needed when speaking in general terms. Same goes when one refers to "nonmetals": the presumption is that someone is referring to nonmetals other than noble gases, unless they have specifically referred to the noble gases. However it is convenient when you want to talk about the non-noble nonmetals to be able to refer to them collectively as other nonmetals. And the other nonmetal name would still show in the info boxes for the applicable elements.

The comparison of properties section of the article would then have three rather than four columns: one for metalloids (given their nonmetallic chemistry), one for other nonmetals, and the last for noble gases. The other nonmetal column could be split into two with a dotted border between them (i.e. to indicate that the border is not always sharp). One sub-column would be for H, C, N, P, S, Se; and the other for O, F, Cl, Br, I, in order to show the contrast between the two subsets of nonmetals, noting neither half of the column is named. The blurb introducing the table will explain the basis for this semiquantitative treatment i.e. oxidising power; covalent v ionic bonding tendencies with metals: corrosive behaviour; ionisation energies, electronegativities, electron affinities, and simple anion formation.

This approach is an attempt to highlight and preserve the interesting progression of nonmetallic character seen in the vicinity of the nonmetals, and to make the nature of the seemingly rag-tag collection of the nonmetals in the other nonmetal placeholder category more transparent. I hate obfuscation, which is what the placeholder category of other nonmetals usually conveys.

I know the term "other nonmetal" is unpopular but as an encyclopaedia we have insufficient leeway.

In summary, I am trying to accomodate as best I can the views of both camps i.e. those who supported and those who opposed the original proposal, and clarify a good amount of realistic complexity (namely the omnium gatherum that is the other nonmetals) without misleading anyone.

@R8R:, @Double sharp:, @YBG:, @DePiep:, @Parcly Taxel: I ask that you consider this proposal carefully and to please not get unduly concerned about the name "other nonmetal". It is not a real category, only a placeholder for the rest of the nonmetals. Despite the "resting place" connotations of the term, there are still some interesting observations that can be made about nonmetals in this space.

We did talk about calling the two categories "nonmetal" and "noble gas" however this is cognitively dissonant (does it mean noble gases are not nonmetals?), unless you happen to look at the legend. And the legend boxes for the periodic table in the top right of the nonmetal article would presumably have to read "Nonmetal" (other than noble gases), and "Noble gas".

I recall that an "other nonmetal" category appeared on our periodic table for many years, with no controversy until I stirred things up. Mea culpa. In retrospect I agree with R8R that the poly-di categories were a split for the sake of having a split. I see no need for the reintroduction of the other nonmetal category to raise any angst, given the considered way I am proposing to deal with it now (and the practice of and

Having written all of this, if anybody is going to die in a ditch about the name "other nonmetal" it won’t matter much to me since I can still write about the properties of this bunch of nonmetals in the way I have described, although I will have to use more clumsy phrasing like, "The nonmetals other than the noble gases are characterised by…etc".

This is what I am talking about, as per and, and the way Wikipedia used to be:

Alkali metal Alkaline earth metal Lan­thanide Actinide Transition metal Post-​transition metal Metalloid Other nonmetal Noble gas Unknown chemical properties
Scheme I

In the above option the relevant sections of the nonmetal article section would go something like:

Other nonmetal
There are eleven such nonmetals: hydrogen (H), carbon (C), nitrogen (N), phosphorus (P), oxygen (O), sulfur (S), selenium (Se), fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). In periodic table terms they largely occupy a position between the weakly nonmetallic metalloids to the left and the noble gases to the right.

The other nonmetals have a diverse range of individual physical and chemical properties…

Noble gas

The other way is:

Metal Metalloid
Nonmetal Unknown chemical properties
Alkali metal Alkaline earth metal Lan­thanides Actinide Transition metal Post-​transition metal Noble gas
Scheme II
Updated 12 Oct to make clearer my personal preference that metal, metalloid, and nonmetal are super-categories; that metal spans six categories; that metalloid spans none; and that the nonmetal super-category has one category. Just as the seven metalloids are not further categorised below their super-category level, neither are the eleven nonmetals that are not noble gases. In classification science terms I suspect that if we can have a super-category that spans several categories, and another one that spans none, then a super-category with one category should be nothing unusual. Sandbh (talk) 05:07, 12 October 2017 (UTC)

In the above option the relevant sections of the nonmetal article section would go something like:

Nonmetal (other than noble gases)
There are eleven such nonmetals: which are hereafter, for convenience, referred to as other nonmetals (strikeout added Sandbh (talk) 05:07, 12 October 2017 (UTC)) hydrogen (H), carbon (C), nitrogen (N), phosphorus (P), oxygen (O), sulfur (S), selenium (Se), fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). In periodic table terms they largely occupy a position between the weakly nonmetallic metalloids to the left and the noble gases to the right.

The other (Sandbh (talk) 05:07, 12 October 2017 (UTC)) nonmetals in question have a diverse range of individual physical and chemical properties…

Noble gas

Sandbh (talk) 05:45, 20 September 2017 (UTC)

Allow me to add another scheme:
Metal Metalloid
Nonmetal Unknown
Alkaline earth
Scheme IIa
I'd like to get rid of the white spacing between the two patches of nonmetal color. This is my attempt to show that the noble gasses form just a subset of the nonmetals but that there isn't a specific name for the NNNM. YBG (talk) 06:50, 20 September 2017 (UTC)
(further threaded discussion moved below to #Comments from YBG. YBG (talk) 06:39, 21 September 2017 (UTC)

Nonmetals: Discussion[edit]

Comments by Double sharp[edit]

I'm really sorry, but using "other nonmetals" without qualification, and without saying at least once what they are other too, still sounds really weird to me. It makes it sound like a term in itself. I know we've been through this with "transition metals", but the truth of the matter is that "transition metals" has become a standard term in chemistry with a sharply defined meaning (groups 3 to 11, and maybe 12), while this is not true for "other nonmetals".
On reading the response to your RfC above, I think one of my priorities in categorisation would be to not make up new terms by ourselves. I think we are all agreed that some nonmetals are more reactive than others, but I think we would also agree that we cannot make a blanket statement that P is less reactive than I; P is more likely to catch fire at standard conditions, after all. At the most we can use something that is indisputable and quantitative that nevertheless correlates reasonably and suggests the trend at work.
I think the greatest strength of the polyatomic/diatomic classification is that it is quantitative and, well, correct enough that it does not attract argument. No one can argue that, in their standard states, C, P, S, and Se are polyatomic, and H, N, O, F, Cl, Br, and I are diatomic. Reality is fuzzy and I would not be fussed if this one predictor of reactivity is not universally applicable, with a commonly encountered polyatomic allotrope of O, as well as the odd cases of H and N. There are many other factors at work, but it would be the height of folly to disregard them all because none of them explain everything by themselves.
Reality is always fuzzy, so we cannot use that directly as a categorisation. Every categorisation implies a certain straitjacketing of reality to fit the narrative, whether it be categorising chemical elements (is Bi really a metal?), musical styles (is Schubert really a classicist or a Romanticist?), or languages (what is a dialect, really?). But the power of categorisation is that it lets us suggest the more complex underlying reality, and provide us with a welcome beginning trail while we learn to navigate the terrain there – provided that we do not take the trail too seriously, and remember that it is only a guide. Double sharp (talk) 06:05, 20 September 2017 (UTC)
P.S. On reading through the archives I strongly suspect that "other nonmetals" as a category would end up being about as well-received as "other metals" was in the past: that is, not well at all. Double sharp (talk) 07:09, 20 September 2017 (UTC)
Plus that "other nonmetals" may be defined differently in other wikis, usually the nonmetals remaining after halogens are categorised too (as NG's are) (see de:Nichtmetalle). While this my look a wikipedia-issue only, it probably signifies an understanding in RL chemistry too. Note that this is about the category naming only, not its existence. -DePiep (talk) 15:36, 20 September 2017 (UTC)

Comments by DePiep[edit]

A strong step this is, Sandbh, after all that effort in an other direction.

  • Procedural: See WP:RFCEND. I'd prefer not to have closing conclusions, since those could impede or prejudice future development. (For example, if a conclusion would be "not acceptable to devide the other nonmetals into subcategories" --I made one up--, we'd be blocked for any other improvement in this). Better would be to, e.g., withdraw the RfC, and allow using the comments, so rich in content, for next steps. And maybe wait one more week to gather some more? -DePiep (talk) 06:38, 20 September 2017 (UTC)
  • In overview, I see separate angles of objection:
1. The new categories not being mainstream or even in stream (fringe science; OR even?),
2. The proposed names of the categories,
3. The actual categorisation per element (includes category definition and border issues),
4. The 'right' to categorise at all, being an encyclopedia not a journal.
I mention them here because they may recur, and need to be distinguished. Also, this list may be up for improvement & refinement. -DePiep (talk) 06:38, 20 September 2017 (UTC)
It's a step back. The fact that top-category metalloids has one subcategory (metalloids) is OK: they are the same. BUT, subcategorising nonmetals into noble gases only is inconsistent: elements are disappearing. This way both vertically (subcategorisation) and horizontally (completeness of both rows) the categorisation is loosing its coherence and relevance. Letting go those principles in categorising should be done for dire reasons, not for the awkward-name-reason. IOW, it is getting uselessly chaotic.
It occurs to me that all this is because one dares not pointing to an existing category, only because it has trouble finding a name. This is entering through the wrong door. If we can point to that RL category, finding a name should not obstruct that fact or category creation. (I note that before 2013, and in other wikis and in other PT charts and literature, category "other nonmetals" is used—however awkward, for lack of a better name, but legit). -DePiep (talk) 06:22, 12 October 2017 (UTC)
Yeah, but the categories are themselves a construct that we impose to emphasise the order that permeates reality to wrap our heads around it. ^_^ That's why depending on what you're trying to show, you might categorise N as a diatomic nonmetal, a less active nonmetal, just a plain nonmetal, a pnictogen, a first-row element, or even a metal (this if you are an astrophysicist). But all these categories are trying to tell us something about what the behaviour of N is like. Using "other X" just defines it by what it is not, and it is not behaviour that is so characteristic that not following it is itself characteristic, as in the case of metallicity vs non-metallicity.
TL;DR: The categories don't really "exist", but are just a combination of what's most useful in most circumstances, which is why we jump ship from periods and groups to metallicity once we pass the Cu-Ag-Au triad. If something doesn't have a name in itself, it is a worrying sign that it may not be all that useful. Double sharp (talk) 08:42, 12 October 2017 (UTC)
re Double sharp All categories are abstract constructs, and this way do exist in real life & in sources. In this categorisation scheme, we don't just add a 'useful' category. We also look for PT-completeness (this why, for example, we don't use the otherwise clear cut set of 'rare earth metals'). Second, again you are dismissing a category only because it has 'non' in its name. So that is dismissing because of the name-quest. 1: we do not do that for the existing "post-" and "transition" name parts. And rightly so, because names may be this relative because of the cover-all principle. If we'd drop that principle because of a name issue, we are loosing the structuring principle, and its PT-relevance. 2. Also, it can be easily solved by picking another name for the same category ("chemically active nonmetals" fits best I think). -DePiep (talk) 11:17, 14 October 2017 (UTC)
@DePiep: Do not lose hope as there may be a better solution, which I talk about towards the end of this post.
It must be frustrating that the way nonmetals are categorised in the literature lacks scientific rigour. Chemistry can be like that. Nevertheless, I do not see that our colour category legend loses its coherence and relevance. It seems straightforward that the nonmetal super-category contains some nonmetals grouped at that level and some which are categorised as noble gases. The same situation occurs with the transition metals in that some are categorised at that level and some are further subcategorised at the level of noble metal or refractory metal. It does not matter that within the transition metal category there are some metals at that level and some others at a lower subcategory level. Of course we do not show, for example, the noble metals in our colour scheme but that does not matter since it is the principle I am advocating for rather than its application. If it is OK for a noble metal child to coexist with a transition metal parent it should be OK for a nonmetal parent to coexist with a noble gas child.
If I can draw a loose analogy with zoological naming conventions, there is something called a type species which is the species that a genus is permanently associated. For example, Cygnus cygnus, the whooper swan, is the type species of the genus Cygnus. In the case of our nonmetal super category, this is the genus, and within that genus is (1) the type species nonmetal nonmetal and (2) the noble gas species. Calling one of our categories nonmetal nonmetal is clumsy so we drop the second nonmetal and simply leave this species at the genus level. The idea is to quickly and simply segment the elements into convenient sets. With respect, I feel this is a human sense thing rather than a matter of sharply defined science.
@Double sharp: The NNNM used to be called nonmetals in the days when the inert gases were thought of as inert i.e. neither metal nor nonmetal. And nonmetal was a perfectly useful category name. Then it was discovered that some of the inert gases could in fact be chemically reactive so the inert gases became the noble gases, and they were generally admitted to the nonmetal club. So the category name nonmetal is still useful as long as it is borne in mind that some of them are noble. From my reading, this is the approach taken by five of the six books on nonmetals listed at the end of the current nonmetal article (I presume Emsley did the same but do not have his book at hand).
The Argonne National Laboratory's Ask a Scientist site has an interesting discussion on this question re the Classification of Noble Gases. Here, the nonmetals are simply divided into nonmetals and noble gases.
I like the option of treating the eleven non-noble nonmetals as a single bloc (as was the original preference of our project) because the bloc can then be examined according to any other property such as atomic structure; oxidising power; electronegativity; or ionisation energy, or any other split such as one of the four other alternatives included in my first draft rewrite of the nonmetal article, rather than having these considerations dictated by a pre-determined split. And there is a rich story to tell about what is going on within this bloc in accordance with as many properties of the elements in question as seems possible.
If we feel we still need a more respectable looking name then I presume the eleven non-noble nonmetals could(?) be called covalent nonmetals since they all feature covalently bonded structures, at standard conditions, unlike the monatomic noble gases. (We discussed this term previously when it was suggested by YBG in a different context).
So we would then simply have:
   Covalent nonmetal
   Noble gas
I don’t know how much clearer we could get. Personally, I'm fine with Nonmetal and Noble gas, but Covalent nonmetal and Noble gas would be at least as good. I presume @DePiep: and @R8R: would be happy, as would @YBG:? It is a superior and more accurate solution than Other nonmetal and Noble gas, given the capacity of the covalent nonmetals to engage in covalent bonding plays an influential role in determining their properties. As the first draft rewrite said, "Nonmetals show more variability in their properties than do metals. These properties are largely determined by the interatomic bonding strengths and molecular structures of the nonmetals involved, both of which are subject to variation as the number of valence electrons in each nonmetal varies." Sandbh (talk) 07:39, 13 October 2017 (UTC)
The suggested categorization principle resonates well with what I've had in mind for years now. Of course, that makes me happy.
As for the name for this new category, I think the number one rule is to have mutually exclusive names among the color categories. All our names are mutually exclusive so far (TM overlap with lanthnides and actinides by two elements in total, but that's clearly considered a flaw only overcome by how well established the conflicting categories are, not just in Wikipedia but in chemistry in general) and that's just a good thing in general because such a categorization is easier to comprehend, which is good for a general-audience-oriented encyclopedia. Unfortunately, this excludes the possibility of having "nonmetal" as a color category name for as long as Wikipedia claims noble gases are actually nonmetals, too. We ruin our internal consistency otherwise. Similarly, this excludes the name "covalent nonmetals" for many xenon conpounds, for example, are covalent just as well, so we're running into the same overlapping problem.
Personally, I've come to think for a couple of times that using the word "nonmetals" for what we call in this discussion NNNMs could be useful. But while it could go okay in a discussion, the problem I've outlined above is absolutely prohibitive for the name to appear as a color category name in our PT. I wasn't back then aware of any two-word terms for the category, which would indeed solve the problem for me. So yes, we do need a fancier two-word name, but we should limit ourselves to two words; I wouldn't want to use the term outside of Wikipedia mainspace articles otherwise.
My money is still on "reactive nonmetals": it is quite clear what the difference between these elements and the noble gases are. This is not a perfectly precise differentiation, but not a particularly blurry one, either; you do get the difference naturally. "Active nonmetals" will also do. I think it's better to specify that these elements involve in reactions rather than that they are active, but I also think this is somewhat preference-related, so I can overcome that. There haven't been other terms that satisfy the requirements I've listed above to my knowledge and I consider them to be necessary to fulfill. If there are any other names that fulfill them, I'm willing to consider them and I'm sure that so is everyone.
@Sandbh: does that make a point for you?--R8R (talk) 11:36, 13 October 2017 (UTC)
Hi @R8R: good to hear from you. It seems to me you may have misunderstood the rationale for calling the NNNM covalent nonmetals. You may as well rule out diatomic nonmetals on the basis that some of the noble gases form diatomic compounds. Instead, the covalent refers to the structures of the nonmetals, not to the nature of their compounds. Thus, the NNNM have covalent structures. S for example, as S8, is a covalent nonmetal. The noble gases have single atom monatomic structures. The distinction between the NNNM and the noble gases, on this basis, is sharp and *widely* recognised in the literature.
Reactive nonmetals is fine by me although Double sharp has expressed a reservation about the relatively reactive nature of Rn.
In taxonomic terms, the name nonmetal need not be a problem if taxonomic conventions are rigidly observed. By this I mean that nonmetal becomes the type species of the genus nonmetal. And strictly speaking, metalloid would need to be recognised as the type species of the metalloid genus. Thus we would need to show:
    Noble gas
The structure and integrity of the categorisation legend is thereby preserved.
I am otherwise very pleased to say we are thinking in a resonant fashion. This includes the general-audience orientation of our encyclopedia, rather than what we tend to focus on which, in my opinion, are dead-end, highly specialised, disorienting, and mentally deranging rabbit holes, rather than pragmatic solutions. I mean no disrespect to anyone in saying this. It's how I feel. We do need to have these discussions to test our thinking but sometimes we lose the continuous improvement plot. Sandbh (talk) 08:08, 14 October 2017 (UTC)
I see; then yes, this is a valid categorization principle. However, a major objection from me comes to the fact I have not correctly understood the name "covalent nonmetals" by just looking at it. That is to say, if there is a name following this principle that does not cause this confusion, I'll want to consider it.
At the moment, it appears to me, however, that chemical reactivity is a better basis for a category name than structure of the simple substances. But if there's a valid name based on that principle, I wouldn't want to reject it right away and would be ready to give it a good thought.
The comment re radon's activity did worry me. Based on the basis of our Wikipedia article alone, however, I think it will be fair not to list radon as a reactive nonmetal on a good basis and not on the basis that it is marginal and none will notice anyway:

Being a noble gas, radon is chemically not very reactive. However, the 3.8-day half-life of radon-222 makes it useful in physical sciences as a natural tracer. Because radon is a gas at standard conditions, unlike its parents, it can readily be extracted from them for research. // Radon is a member of the zero-valence elements that are called noble gases. It is inert to most common chemical reactions, such as combustion, because the outer valence shell contains eight electrons. This produces a stable, minimum energy configuration in which the outer electrons are tightly bound. 1037 kJ/mol is required to extract one electron from its shells (also known as the first ionization energy).

I do understand the taxonomy principle but I don't happen to like it for the same reason as I've outlined above: It is confusing for those who are not familiar with it. People will confuse nonmetal the genus and nonmetal the species. The readers get to see the category species long before they get to see the whole picture (infobox vs. the collapsed table at the very end of the article). That is not to mention I genuinely do consider this to be a very poor solution for a categorization problem. I guess the taxonomists can go with whatever they like as long as the get to learn the same stuff and all understand it. (Possibly they also named genuses (or gena) after the single species they could assign to this genus and only then they found some other related species and assigned it to the named genus?) We are, however, dealing with a general public that probably can't and most certainly shouldn't be made learn our notation; the notation must come naturally as long as it's possible.--R8R (talk) 11:00, 14 October 2017 (UTC)

@R8R: I'm quite pleased to say that, as a pragmatic solution, I quite like reactive nonmetal. This would then give us:

Scheme IV

These two category names make for a nice pair. "Reactive" is more general-reader orientated than "covalent". It may be a bit fuzzy for the chemistry professional but is close enough, and cp's do not represent our primary audience. (Up to 2007 only about half a thousand noble gas compounds had been synthesised, whereas as at 1987, the Chemical Abstracts Service had recorded 8.4 million chemical species of all kinds. The contrast is sobering.) The two categories have no taxonomy presentation issues. Curiously, Nergaal seems to have first made the suggestion to use the term reactive nonmetal, in September 2012. But for my obsession with splitting the NNNM we would have already been there. ¡Ay, caramba! Headslap! Sandbh (talk) 06:18, 16 October 2017 (UTC)

I would likewise support "reactive nonmetals". Double sharp (talk) 10:26, 16 October 2017 (UTC)
With this progress I guess the genus-type issue is moot, as it is not used. I'd support the scheme, and have no strong opinion on the exact new category name because my chemistry reading is too limited. -DePiep (talk) 12:50, 16 October 2017 (UTC)
Huzzah! from down under :) Sandbh (talk) 05:13, 17 October 2017 (UTC)
I quite agree. "nonmetals" = "reactive nonmetals" + "noble gasses" is a very good solution to the entire issue. YBG (talk) 04:10, 18 October 2017 (UTC)

Comments from Parcly Taxel[edit]

We already had the conclusion for what to call the other nonmetals earlier: the chemically active nonmetals. Nevertheless, I'm so concentrated on life in university that I won't need to contribute anymore to this project – or even Wikipedia.

I can finally do the mathematics I always wanted to do. I'm looking to go to the Sorbonne or some other French university in 2019 or 2020 to play the game at its very best. So this, after six years, I hope will be a final farewell. Parcly Taxel 08:09, 20 September 2017 (UTC)

What a great view. Future and ambition! Enjoy and soak it all, is my wish for you. I still hope we will read more from you here. And thanks, F = FA for example. -DePiep (talk) 17:29, 23 September 2017 (UTC)

Comments from R8R[edit]

I think this is a step in the right direction, but not quite there yet.

First of all, I have carefully analyzed what you have written. The problem is that most readers won't even know there is something to analyze because most readers won't click the link and won't read the article nonmetal. Second of all, I would easily consider it a bad design if we had a colored metal category without a single element being colored as one. So I'd down vote the versions II and IIa. Version I is worth investigating into, though.

I see why you're thinking of the possible "other nonmetal" (regardless of the name) category as of an untercategory, if some German is allowed. I've been thinking something along these lines myself, so I quite understand this thinking. I have said I could give up my support on this category if there ever was a good break, and I've meant it; the problem is, there hasn't been one and I no longer believe there is one at all. (Though I remain open-minded on this one to new suggestions.) However, I don't find it necessary to underline so much that these elements have nothing in common so they don't have a defining characteristic when there clearly is one: they are reactive unlike the noble gases. Even nitrogen (the element; the periodic table is filled with elements, not substances they form at STP) is clearly reactive. This is a clear definition if you apply the common sense just like you do not to count all nonmetals as monoatomic because they are at some extreme conditions. We could have "reactive nonmetals" and keep on thinking that this isn't the perfect category but the best thing we've got. That'd be fine by me. If this name still isn't good enough, we also could go with "chemically active nonmetals"; that's, too, a fine name. How's that sound?

To summarize the previous paragraph, I believe a not-so-perfect category and a proper name is better than a not-so-perfect category and a poor name, and there are genuinely good options regarding the name for this category on the table.--R8R (talk) 18:07, 20 September 2017 (UTC)

Comments from YBG[edit]

Two comments

  • In retrospect, it may have been better to use "corrosive nonmetals", as I think it may have removed some of the uncertainty as to whether N and P belonged in that category. But that may not have made any difference, and even if it had, it's water under the bridge now.
  • When a category has a proper name, it is helpful to consistently use it in each and every situation - paragraphs, infoboxes, charts and diagrams, the whole lot. But when a category has no perfect name, it may be that different terms are suited in different situations. After mentioning the inertness of the noble gases, it would be perfectly natural to say something like, "On the other hand, the chemically reactive nonmetals ...." Other sentences might work best simply saying "the other nonmetals" or even "the non-noble nonmetals". By avoiding an absolutely rigid insistence on consistent nomenclature, we could choose to use the descriptive phrase best suited to each circumstance.

Just a couple of random thoughts. YBG (talk) 04:42, 21 September 2017 (UTC)

(Here follows a threaded discussion moved from above) YBG (talk) 06:39, 21 September 2017 (UTC)

Allow me to add another scheme:
Metal Metalloid
Nonmetal Unknown
Alkaline earth
Scheme IIa
I'd like to get rid of the white spacing between the two patches of nonmetal color. This is my attempt to show that the noble gasses form just a subset of the nonmetals but that there isn't a specific name for the NNNM. YBG (talk) 06:50, 20 September 2017 (UTC)
re YBG: Scheme IIa is an improvement, because each row now is a full & complete categorisation scheme by itself (just the zoom level changes: general or detailed). Scheme II misses the "other nonmetals" in the bottom row, making that row incomplete. re whitespace: so far we've not added a meaning to the border (in the scheme), let alone variant borders. I don't think the scheme itself (the graph) is the place to add this. Expect it to be described in article(s); see metalloids for example. -DePiep (talk) 15:47, 20 September 2017 (UTC)
re "so far we've not added a meaning to the border" I'm not proposing to add a meaning, I just think that removing the white space would subliminally emphasize the fact that  Nonmetal  in the upper row and the       in the lower row both use the same color. YBG (talk) 04:57, 21 September 2017 (UTC)
Now I see. Well, as theym are different categories (by definition, by element list), they should have different colors (unlike metalloids). But we'll get to this in the end, color is editorial only so not an issue now. (For clarity, you could use that new yellow or green one for the smaller box). -DePiep (talk) 05:37, 21 September 2017 (UTC)

(end of moved discussion, the remainder was created here)

I suppose I should have created both Scheme Ia and Scheme IIa as follows:

Schemes Ia & IIa: YBG's versions of Sandbh's Schemes I & II
Metal Metalloid
Nonmetal Unknown
Alkaline earth
Metal Metalloid
Nonmetal Unknown
Alkaline earth

First of all, when I looked at Sandbh's Scheme I, what I actually imagined in my head was Scheme Ia. But on reflection, the lack of the first row ay or may not have been intentional, so I have here created Scheme Ia. Now I understand the desire of DePiep to distinguish different (sub)categories by using different colors. But if we do that, there is virtually no difference between Scheme Ia and Scheme IIa.

The point of Scheme IIa is to show, by repeating the color, and by using a narrower box showing no name, that the 11 NNNM are somehow or other NOT a full-fledged category, that is to say, they lack their own defining properties and have no proper name. Personally, I don't like this sort of categorization, I want categories to be mutually exclusive and jointly exhaustive. But if what we want to say is that these 11 aren't a subcategory but merely the leftover elements after removing the NG from the NM, then Scheme IIa is precisely the way to show that. What I dislike about Scheme IIa is not its re-use of colors, but the presence of 11 elements that don't have their own 2nd level subcategory. I really don't like that. But if I want to illustrate that categorization, then Scheme IIa, complete with the re-use of the color, is IMHO, the best way to illustrate it. YBG (talk) 06:39, 21 September 2017 (UTC)

I have succeeded in removing the white inter-cell margin from Scheme IIa above. YBG (talk) 06:55, 21 September 2017 (UTC)
We should dissociate the questions of (1) whether a categorisation is a good idea and (2) whether a legend is showing it well, and while I am so far not convinced of (1), I am certainly convinced of (2) here. Double sharp (talk) 07:10, 21 September 2017 (UTC)
@Double sharp: You managed to communicate in a single sentence what took me two paragraphs. Bravo! YBG (talk) 07:23, 21 September 2017 (UTC)
@YBG: Thank you! Double sharp (talk) 07:25, 21 September 2017 (UTC)
I added an expansion to a previous comment, marking it with superscript text. YBG (talk) 07:42, 21 September 2017 (UTC)
And I have now managed to restore the white borders between differently-colored cells while retaining the joining of the two      -colored cells. YBG (talk) 07:57, 21 September 2017 (UTC)
And much as I dislike Scheme IIa, think for a minute about what you would expect to see in an article entitled "Chemistry of nonmetals" or "Electronegativity of nonmetals" or similar. I think you'd expect to find information about the 11 NNNM. While everyone agrees that the noble gases are nonmetals, I think that in the context of chemistry, you wouldn't expect to see information about noble gases unless you are explicitly told to expect it, as if an article was called "Electronegativity of the noble gases" or perhaps (gasp!) "Chemistry of the noble gases and other nonmetals". Or consider the sentence: "Nonmetals tend to form ionic bonds with metals covalent bonds with other nonmetals." I have no idea how NG bonding is analyzed, but it seems to me that no one would read this sentence and start thinking about noble gases. Well, no one except for nerds editing an encyclopedia, who therefore are always thinking about not just the specific things in focus but also all the rest of the WP:ELEM universe. Does any of this make sense to anyone? Or am I (once again) making a fool of myself by trying to make too much of my limited knowledge. Enlighten me, please. YBG (talk) 08:26, 21 September 2017 (UTC)
I might agree for He, Ne, and Ar, whose chemistry is rather vacuous. But I suspect that most chemists would think of Kr, Xe, and Rn as fairly normal elements which comport themselves chemically rather like their neighbours Br, I, and At one oxidation unit lower. After all, compounds like KrF2 and XeO3 are fairly clearly covalent, and are clearly analogous to [BrF2] and [IO3] respectively. (RnF2 is I guess an exception, but even PCl5 is on the covalent-ionic divide already.) After all, R. Bruce King's book on main-group chemistry covers groups 17 and 18 in the same chapter. ^_-☆ I don't think I would treat Kr, Xe, and Rn as not being nonmetals, and I don't think anyone would either: and the marginalisation of He, Ne, and Ar is only because they have no chemistry to talk about at standard conditions. Double sharp (talk) 09:03, 21 September 2017 (UTC)
P.S. Powell and Timms' The Chemistry of the Non-Metals includes the noble gases, the eleven NNNM's, and the metalloids. (And while I might quibble about whether the ontological approach is most appropriate here, I think it's unquestionably true that ontologically, metalloids are non-metals. I include the hyphen to differentiate "non-metal", which to me implies the ontological approach, from "nonmetal", which may have some independence in its definition from that of a metal.) Double sharp (talk) 09:07, 21 September 2017 (UTC)
#Scheme IIa is inacceptable, because you declare two different categories the same (by intentionally using the same color). The scheme has this to convey: row 1 = categories metal-metalloid-nonmetal, and row 2 = alkali metals-...-noble gases. Each row by themselves is mutually exclusive and jointly exhaustive (good wording!). The vertical connection is: "x is a subcategory of y". When a category is defined exactly the same above and below (metalloids), they can & should use the same name & color. However, not so for the Scheme IIa "nonmetals [row 1]" vs "some nonmetals [row 2]". With this, changing the border is trivial and has no meaning. And I repeat: this only needs to be solved once we have some agreement on those 11 nonmetals category (unless you really want to shake up the bigger scheme, which I did not read). -DePiep (talk) 09:46, 21 September 2017 (UTC)
It seems to me that the primary purpose of a legend is to be easily understood, not to conform to some hard-and-fast rules that usually correlate with easy understanding: that is similarly why abuses of notation exist in mathematics. So I do not see the problem in the colouring: it may be unusual, but I think it is clear to everyone what it means. (I may revise this position if someone can come up with a plausible alternate reading of the legend pictured.) Rather, I would critique the categorisation. But that is a different issue, as I have already stated above. Double sharp (talk) 09:56, 21 September 2017 (UTC)
It's not "unusual", it is dead wrong because it breaks the categorising principle. This way, two categories are defined both named "nonmetals" while one contains all nonmetals and the other one contains just eleven. Nonsense, to be rejected before causing headaches. "it is clear to everyone what it means": no, it has (actually: "they have") two different meanings so "it" can not be clear. We are not in need for such informal nudge nudge wink wink concepts. -DePiep (talk) 16:19, 21 September 2017 (UTC)
(Also, it is unclear which problem is actually 'solved' this way). -DePiep (talk) 16:19, 21 September 2017 (UTC)
I think you're expecting a sort of strictness in categorisation that is simply not present in the way the terms tend to get used in chemistry. Contrary to what the pretty colours everywhere tell us, element categorisation is a fairly fuzzy concept, and chemists simply don't expect them to be mutually exclusive or jointly exhaustive; they would simply mix and match whatever analogy or grouping is most germane to the situation at hand. It just so happens that some categories are more often used than others, and are thus more "standard" in the sense that people understand what they mean. But it is indeed, as you put it, very much an "informal nudge nudge wink wink concept" compared to the groups.
The idea here is simply that you have these 17 nonmetals, and while you can group some together as noble gases, the others don't really have any standard name for them. If it is that much of a problem to display this reality, simply because it doesn't provide neat little boxes, I would much rather avoid splitting the nonmetals at all, and simply let the little "18" at the top of the column take care of the noble gases. Double sharp (talk) 00:16, 22 September 2017 (UTC)
P.S. The WP categories are not even mutually exclusive anyway: since we consider La to be in group 3, the IUPAC definitions mean that La is both a lanthanide and a transition metal, and similarly Ac is both an actinide and a transition metal. Double sharp (talk) 00:19, 22 September 2017 (UTC)
Again, what problem is being solved? I get the strong impression that because some people have difficulty with naming a category, they want to abolish an RL existing category. (and P.S.: both otherstuffexists and border issues do not count). -DePiep (talk) 16:01, 22 September 2017 (UTC)
The problems lie in your sentence "RL existing category". First is the assumption that these categories exist in real life. They don't: they are just human constructs aimed at organising the messy reality before us. That is why every supposed category has its more or less representative members. The groups and periods have more of a real existence, because they simply ask one scientific question: "how many electrons are there in the valence subshells?" or "how many subshells are filled?". You can give a yes or no answer to those. Categorisation asks a different question: "how should I split the elements for my purposes?". Scientific inquiry can give you suggestions to the answer: it can tell you what commonalities are illuminated and which are obscured by each split, as well as the same for the differences. But at the end of the day the decision is yours based on what you think is more important to show, and science isn't going to tell you that. There's a good reason why group and period are words you learn in first-year chemistry, while category is not. If it were really that clear-cut, then perhaps we would have stopped the never-ending differences in the boundaries of the metalloids, which have ranged from including nothing to just about everything in the p-block.
The other problem is in the assumption that the set of elements {nonmetals} \ {noble gases} has a standard name. The fact that we can't seem to think of anything better than "non-noble nonmetals" seems to show otherwise, and indeed you will be hard-pressed to find anything else in the literature in case this group is meant. It is kind of like a supposed set {metals} \ {alkali metals}; if this set is ever needed for some freakish reason, there is certainly a way to describe it, but it is not at all a standard way to slice up the periodic table. (BTW, regarding "chemically active"; Rn is chemically active enough that there have been serious proposals to use chemical reactions to absorb it from air, just like is done with CO2.) Double sharp (talk) 06:46, 23 September 2017 (UTC)
────────────────────────────────────────────────────────────────────────────────────────────────────(outdent) re. About our right to categorise, and use names for categories. I beg to differ on the statement "the assumption that these categories exist in real life. They don't". The categories too are based on a question, like groups and periods are, this time like: "which elements show non-metallic, inert behaviour" or so. The answer lies in nature, and can be found empirically, and then be published. Not my personal opinion. Sure border situation elements exist, but that does not undo the element clustering, i.e., some elements gathering closer to the core claim a category makes. The 118 elements are not randomly or continuously spread wrt such properties. Categories are not taught in first year chemistry? Does not say anything about their existence in RL. Sure, some are more important or strongly defined or used in practice, and some are fringe science (as the two RfC'ed categories are I understand). Altogether: categories exist in nature, can be researched & sourced, and so this encyclopedia has a right to describe them.
About completeness. This being the periodic table, it is worth covering the whole once when possible. That makes the categorising way way more meaningful, as it illustrates a trend in the periodic table. For this reason, border issues are to be neglected (well, declared less important), and scholars are supposed to get that. For this reason too, we can rightly add less-important categories to cover all, instead of allowing white 'undeclared' areas that actually are declarable (An example of ~non-trend information could be state of matter @STP, and other properties more randomly scattered in the PT; cristallisation?). Such is the history of the periodic table: Mendeleev too accepted irregularities to show the broad view.
Now since we do use the complete, trending categories principle, we are not free to leave that incidentally. That would undo the categorisation background, would leave the scheme less useful for what it tries to show, would break its periodic table relation: would make the scheme worthless. Especially creating one category with two definitions and two element lists (Scheme IIa) defeats all logic, and introduces ambiguity that is nigh impossible to explain/describe/de-confuse/un-soup. The Abuse of notation motive Double sharp mentioned above is useful when it would clarify stuff, but also says: ... the correct intuition (while being unlikely to introduce errors or cause confusion). This, while other options exist (have two distinct categories).
At last, about names of categories. Of course, when an established name exists we use it. However, when such a name is not available, we can rightly introduce a descriptive name. And again because of the trend reason I mentioned above, it is acceptable to use relative category names, such as "non-...", "post-", "elements that are not ...". An article or section can describe it, giving context. Also less-prominent classifications can be rightfully described in articles. E.g., pointing out the corrosive nonmetals as is done in Sandbh's nonmetal article proposal is perfectly acceptable (though we should not publish those broadly in our standard PT because fringe). For this, relativeness and descriptiveness, names like "other nonmetals" and "non-noble nonmetals" are OK, and also "the elements: ..." or "category that has no name for weird reasons"; all with grades of best-ness. Any such a name is better than no name. re "if this set is ever needed, ...": I don't agree with the 'it's not used/needed/taught' reasoning to accept/reject a category (in the RfC this was brought forward too). If it exists & sourced, we can use it. Some categories are more 'fringe' (less commonly referred to) than others, but when lacking anything better we can use it. Here too, completeness of the scheme trumps daily usage. -DePiep (talk) 09:20, 23 September 2017 (UTC)
re the RL existence of categories. Yes categories are based on the answers to questions just as groups and periods are. The human/editorial aspect comes in the selection of the questions to ask. Questions about shells and valence electrons are by universal consensus accepted as important questions. Selecting which questions to use for a categorizing scheme has yet to achieve anything like universal consensus, much less WP consensus.
re using names at two levels of a hierarchy. The English language does this all the time, and native speakers find it so easy to disambiguate that they hardly ever notice absent something external that brings it to the fore. For example, the word "man" was once universally used with several meanings, (a) any human being (b) any male human (c) an adult male human. And consider the word "European". If you were to overhear a discussion at a bar in New York complaining about "the European way of doing things", it would mean something quite different than if you heard the same complaint in a London pub. Scientists rightly try to avoid such ambiguity by looking to use words like "continental".
YBG (talk) 20:30, 23 September 2017 (UTC)
re [I'm disappointed] -DePiep (talk) 19:45, 24 September 2017 (UTC) [self-redacted, -DePiep (talk) 19:44, 28 September 2017 (UTC)]

Comments from Sandbh[edit]

At the moment the status quo of polyatomic/diatomic/monatomic noble gas is what we have. That is fine by me. I would now like to adjust the existing nonmetal article to bring out some more of the interesting properties of the polyatomic nonmetals and the diatomic nonmetals. For example, H is a bit of an odd element among the diatomics but then H is difficult to place generally. But the strongest hydrogen bonds are formed with the most electronegative elements i.e. N, O, F, and that seems another good enough reason to count H along with N, O, F, Cl, Br and iodine, noting as well that the properties of H are sometimes compared to group 17. Sandbh (talk) 02:42, 27 September 2017 (UTC)

I'm not sure current categorisation polyatomic/diatomic/monatomic noble gas would stand an RfC (could look a lot like current one). I'd say split non-metals into two: NG and NNNM. Meanwhile, article nonmetals could be as detailed as its sandbox now is (with a few tweaks in periodic table connection, reflecting the categories). -DePiep (talk) 20:43, 27 September 2017 (UTC)
We won't need an RfC since the current scheme stands, which is polyatomic/diatomic/noble gas. Sandbh (talk) 23:19, 27 September 2017 (UTC)
Sure we don't need one. But... anyone could start one, and then we can expect the same arguments & consequences. -DePiep (talk) 10:50, 29 September 2017 (UTC)
  • What would it take to close the current RfC? Should we get an uninvolved editor to do it? It looks like no consensus to me, but ... YBG (talk) 00:20, 28 September 2017 (UTC)
@YBG: Hmm. I can close it. Consensus does not require agreement and many of the opposes are groundless as I now read them. We are not talking about introducing new category names as such, only descriptive phrases to distinguish between different kinds of nonmetal. Let me see how it looks. There sure are a lot of opposes. Sandbh (talk) 04:41, 28 September 2017 (UTC)
@Sandbh: If I were going to do it, I'd close it as 'no consensus' - which is pretty much the same thing as 'oppose'. YBG (talk) 05:43, 28 September 2017 (UTC) YBG (talk) 05:44, 28 September 2017 (UTC)
@YBG: Noted. Sandbh (talk) 05:45, 28 September 2017 (UTC)
In this case I would much prefer to leave the closure to an uninvolved editor. I was okay with you closing the one on group 12 because it really was unanimous, but I think the opposition has made some quite pertinent points – notably that putting descriptive phrases in this prominent a position effectively transmutes them into new category names. Double sharp (talk) 06:07, 28 September 2017 (UTC)
Formal closure (by anyone) could leave us with explicit conclusions that could hinder the issue development in the future (some road may be closed in general). An other option would be 'withdrawal' by Sandbh, (then we still can digest & use comments). And re YBG: I don't think 'opposed' is the same as 'no consensus' in this situation. See also WP:RFCEND. -DePiep (talk) 06:40, 28 September 2017 (UTC)
@DePiep: Thanks for the link. My comment re oppose=no-consensus was merely meaning to say that both results leave WP articles in their status quo ante. I was not considering the long term, which you helpfully considered. And I agree 100% that the best result would be for Sandbh to withdraw the RfC, i.e., to end it by removing the {{rfc}}. YBG (talk) 04:30, 30 September 2017 (UTC)
BTW, I'm preparing a sort of basical reply in the RfC, I could use one more day. -DePiep (talk) 06:42, 28 September 2017 (UTC)
  • @Sandbh:. In this thread's OP you advocated to use something like "other nonmetals" (unfortunately is was about that name only, not about the correctness of that category, but alas). I thought that was to introduce a single category for the NNNMs. But now you state that the two poly-/di-atomic nonmetal categories are fine. Would you feel strong about one to the two options? (As said, describing all categorisations in the article nonmetal is fine, and is not limited by our main category set in any way). -DePiep (talk) 10:55, 29 September 2017 (UTC)

Response to DePiep
@DePiep: I haven’t replied so far as I’ve been stumped for an answer. I proceed with the greatest of trepidation in submitting the following thoughts.

The marvelous variety and infinite subtlety of the non-metallic elements, their compounds, structures and reactions, is not sufficiently acknowledged in the current teaching of chemistry.
JJ Zuckerman and FC Nachod
In Steudel's Chemistry of the non-metals (1977, preface)

In trying to understand the nonmetals I think there are seven perspectives to consider:

(1)  The general properties of nonmetals at standard conditions e.g. volatility, low elasticity, good insulators, they gain or share electrons when they react with other elements or compounds.
(2) Their structures, nonmetals having a low number of nearest neighbours compared to metals.
(3) Which of their properties are surpassed by some metals e.g. the ionisation energy of Hg exceeds that of S and I; the electronegativity of Au exceeds that of P; the electron afinity of Cd is less than than that of N.
(4) Their anomalies e.g. H’s uniqueness; N’s low electron affinity and relative inertness, P4’s reactivity; Xe’s relatively low ionisation energy; first row v second row differences.
(5) The chemistry of the nonmetals by group.
(6) Patterns and trends among the nonmetals in ionisation energy, electron affinity, electronegativity and oxidising power.
(7) Cross-cutting relationships.

I think if you can keep all this in your head than you can follow why the nonmetals are as diverse as they are. The current nonmetal article only largely does (1) and (2). The rewrite adds some of (4) and (5); a little of (6); and (7). A further rewrite would add or expand (3); (4); (5); and (6).

I tend to think a further rewrite might best be done by having only two formal categories of nonmetal: the top-shelf nonmetal category for H, C, N, P, O, S, Se, F, Cl, Br and I; and a single noble gas subcategory (noting the metalloids are similarly in a top-shelf category and have no subcategory).

The nonmetal article might go partly like this:

Nonmetals are H, C, N, P, O, S, Se in group 1 or groups 13–16; F, Cl, Br, and I in group 17; and the noble gases He, Ne, Ar, Kr, Xe and Rn in group 18. For convenience within this article, nonmetals other than the noble gases are hereafter referred to using the descriptive phrase "chemically active nonmetals"; and the four group 17 elements are referred to as "halogen nonmetals". Of these terms only "noble gases" and "halogen" are IUPAC-approved.

The chemically active nonmetals have a diverse range of individual physical and chemical properties. In periodic table terms they largely occupy a position between the weakly nonmetallic metalloids to the left and the noble gases to the right.

Physically, four are solids, one is a liquid (bromine), and six are gases. Of the solids, carbon, selenium, and iodine are metallic-looking, whereas sulfur has a pale-yellow appearance. Ordinary white phosphorus has a yellowish-white appearance but the black allotrope, which is the most stable form of phosphorus, has a metallic-looking appearance. Bromine is reddish-brown in colour. Of the gases, fluorine and chlorine are coloured pale yellow, and yellowish green. Electrically, most are insulators whereas carbon is a semimetal and black phosphorus, selenium and iodine are semiconductors.

Chemically, they tend to have higher ionisation energies, electron affinities, and electronegativity values, and be relatively strong oxidising agents, in comparison to metals. Collectively, the highest values of these properties are found among oxygen and the halogen nonmetals. Manifestations of this status include oxygen's major association with the ubiquitous processes of corrosion and combustion, and the intrinsically corrosive nature of the halogen nonmetals. All five of these nonmetals exhibit a tendency to form predominately ionic compounds with metals whereas the remaining nonmetals tend to form predominately covalent compounds with metals.

Characteristic and other properties of metalloids, chemically active nonmetals, and noble gases are summarised in the following table. Metalloids have been included in light of their generally nonmetallic chemistry. Physical properties are listed in loose order of ease of determination; chemical properties run from general to specific, and then to descriptive. While the table shows the main points of difference it is somewhat arbitrary since exceptions and boundary overlaps can be found within each category, set, or subcategory. Important instances of such are so noted.

In writing this it occurs to me that such an approach might work just as well for the di/polyatomic/noble gases. So, after all that, I still don’t know which one will work best. At least you know I haven’t stopped thinking about this/working on it.

I presume project members would be happy with either outcome, depending on how the article in question looked. Whatever the outcome my intention is to have a better, more lucid nonmetal article. It may be that I'll have to do both rewrites.

Somewhere, if we do not do so already, we perhaps need to say that:

(1)  our categorisation scheme, and its subcategories, is not definitive;
(2) for convenience and economy of description we…
(a) use IUPAC-approved collective names for the alkali metals, alkaline earth metals, and noble gases;
(b) do not use the IUPAC-approved collective names lanthanoids, actinoids, rare earth metals, pnictogens, and chalcogens;
(c) refer to the leftover elements as either post-transition metals, or metalloids, or "nonmetals" for nonmetals not categorised as noble gases i.e. H, C, N, P, O, S, Se and the halogen nonmetals (akin to the LANL periodic table);
(3) there is a spectrum of properties within each category or subcategory;
(4) it is not hard to find overlaps at the boundaries (see here), as is the case with most classification schemes.

And perhaps these caveats need to be flagged some more in the periodic table article.

I'm not sure if I'm completely happy yet with this post but I feel the need for some feedback, so "Save changes" here I come. Sandbh (talk) 03:56, 7 October 2017 (UTC)

  • This is not my analysis of the RfC. Note that I already quoted & parsed the IUPAC section IR 3.5, with two notable conclusions:
1. IUPAC only lists categories with definite list of elements. Therefor we see no metalloids, metals, nonmetals (under any name), because the metalloids borders are not settled (a top level category btw, and logically spreading this issue to neighbouring categories and into subcategories like PTM, Other Nonmetals.
2. IUPAC does name the sets, but does not describe the sets. There is no description of the "like"-ness of these elements (there is no: in want sense are they "like"?).
Exception to both 1 and 2: transition metals wrt group 12 and d-block.
Now since IUPAC does not recommend 'metals', does that mean we cannot use that? No, we can. Most non-recommended (fully omitted) categories are established concepts, border element issues not denying the concept. More so in the top-level (3 categories, none is recommended). So my conclusion is: we can add a category like 'nonmetals', especially to use and complete the category set.
An other conclusion from the RfC comments, as I read it, is that the new proposed names are WP:FRINGE (that is not: WP:OR!) and therefor not acceptable. It is no big step to claim that poly-/di-atomic names are too. These subdivisions surely can be described in the nonmetal article (as your sandbox does; also subdivisions by other criteria), but can not be our generally published category.
However, the 11-element category is not fringe, and can be given a descriptive name for lack of any established name. A naming issue should not prohibit us of pointing to this category (please keep naming a category separate from category criteria; unlike (1) and (2). A source of trouble). -DePiep (talk) 08:15, 7 October 2017 (UTC)
My position, after the RfC: subcategories are WP:FRINGE (RfC says), we have a due right to categorise, IUPAC Recommendations are only valid for what they do say, the major categories are undisputably correct & acceptable at wiki (metal-metalloid-nonmetal), for completeness (covering the PT to show PT trends) additional categories are needed, any naming issue can nnot be a reason to not categorise. Practically: one category for the 11 NNNMs (Drop the current two per FRINGE), best named "active nonmetals", go detail in the nonmetal article. -DePiep (talk) 09:58, 7 October 2017 (UTC)

Comparative table[edit]

Physical property Metalloid Reactive nonmetal Noble gas
Form solid solid: C, P, S, Se, I
liquid: Br
gaseous: H, N, O, F, Cl
Appearance metallic metallic, coloured, or translucent translucent
Elasticity brittle brittle if solid soft and easily crushed when frozen
Atomic structure close-packed* or polyatomic polyatomic: C, P, S, Se
diatomic: H, N, O, F, Cl, Br, I
Bulk coordination number 12*, 6, 4, 3, or 2 3, 2, or 1 0
Allotropes most form known for C, P, O, S, Se none form
Electrical conductivity moderate poor to moderate poor
Volatility low: B, Si, Ge, Sb, Te
moderate: As, At?
low: C
moderate: P, S, Se, Br, I
high: H, N, O, F, Cl
Electronic structure metallic* to semiconductor semimetallic, semiconductor, or insulator insulator
Outer s and p electrons 3–7 1, 4–7 2, 8
Crystal structure rhombohedral: B, As, Sb
cubic: Si, Ge, At?
hexagonal: Te
cubic: P, O, F
hexagonal: H, C, N, Se
orthorhombic: S, Cl, Br, I
cubic: Ne, Ar, Kr, Xe, Rn
hexagonal: He
Chemical property Metalloid Reactive nonmetal Noble gas
General chemical behaviour nonmetallic to incipient metallic inert to nonmetallic
Rn shows some cationic behaviour[1]
Ionization energy low moderate to high high to very high
Electron affinity low to high moderate to high (exception: N is negative) negative
Electronegativity moderate:
Si < Ge ≈ B ≈ Sb < Te < As ≈ At
moderate to high:
P < Se ≈ C < S < I < Br < N < Cl < O < F
moderate to very high
Oxidation states negative oxidation states known for all, but for H this is an unstable state
positive oxidation states known for all bar F, and only exceptionally for O
from −5 for B to +7 for Cl, Br, I, and At
only positive oxidation states known, and only for heavier noble gases
from +2 for Kr, Xe, and Rn to +8 for Xe
Oxidising power low (exception: At is moderate)
low to high n/a
Catenation marked tendency marked tendency: C, P, S, Se
less tendency: H, N, O, F, Cl, Br, I
least inclination
Compounds with metals tend to form alloys or inter-metallic compounds mainly covalent: H†, C, N, P, S, Se
mainly ionic: O, F, Cl, Br, I
none form simple compounds
Oxides polymeric in structure[2]
B, Si, Ge, As, Sb, Te[3] are glass formers
tend to be amphoteric or weakly acidic[4][5]
C, P, S, Se, and I are known in at least one polymeric form
P, S, Se are glass formers; CO2 forms a glass at 40 GPa
acidic, or neutral (H2O, CO, NO, N2O)
XeO2 is polymeric;[6] other noble gas oxides are molecular
no glass formers
stable xenon oxides (XeO3, XeO4) are acidic
Sulfates most form some form not known
Table alpha Comparative table (by Sandbh)

*Bulk astatine has been predicted to have a metallic face-centred cubic structure
 Hydrogen can also form alloy-like hydrides

It looks much better than what I had imagined. You can see the transition in metallic character going across the three columns. I can see a lot of potential for elaborating, in the article, the trends and patterns occurring in the central column. I'm happy and looking forward to finishing the table and adjusting the article accordingly and our categorisation scheme. Sandbh (talk) 07:48, 8 October 2017 (UTC)


  1. ^ Stein 1969; Pitzer 1975; Schrobilgen 2011
  2. ^ Brasted 1974, p. 814
  3. ^ Sidorov 1960
  4. ^ Cite error: The named reference Rochow_1966.2C_p..C2.A04 was invoked but never defined (see the help page).
  5. ^ Atkins 2006 et al., pp. 8, 122–23
  6. ^ Ritter 2011, p. 10
Commentary & discussion[edit]

Suggestion: In the above table, there are several places where a range is given, e.g., for electronegativity of reactive nonmetals:

Instead of   Moderate to high   we could say   Moderate to high

A further refinement could use << or ≪ for big gaps. It might also be better to show in reverse order. Such a display could have helped the chemically illiterate like me evaluate potential subcategorizations of reactive nonmetals. Just a thought.... YBG (talk) 23:20, 20 October 2017 (UTC)

👍 Like This is a rather worthy suggestion. Sandbh (talk) 02:26, 21 October 2017 (UTC)
There are several other places in the table that say "low to high" or the like. And as a nit, I wouldn't use two bullets since there aren't two separate groups. I might try my hand at changing that to see if it is an improvement or not. YBG (talk) 20:24, 21 October 2017 (UTC)


Note: This section summarizes the consensus of this thread, adopting what has been marked above as "#Scheme IV" YBG (talk) 22:26, 24 October 2017 (UTC)

@Sandbh, Double sharp, DePiep, and YBG: It appears that we all agree that the best subcategorization of nonmetals is into two subcategories, the noble gasses and the reactive nonmetals. Using two subcategories has been accepted instead of three because there seems to be no general agreement on how to subcategorize the non-noble nonmetals (NNNM).

  • (1) The diatomic and polyatomic subcategories while generally unambiguous, with the expected few borderline ambiguities (e.g., P and O); nevertheless, the categorization does not appear to be useful in displaying representing broader trends. Thus, it is rejected as being too close to categorization for the sake of categorization.
  • The other two schemes -- (2) halogens + others and (3) corrosive + others -- have both failed to gain consensus as the best categorization, and the lack of a reasonable name has only exacerbated the difficulties.

Having agreed on two subcategories, we then agreed that the best name for the non-noble nonmetals is "reactive nonmetals".

  • It is understandable to our primary audience, the non-professional (and so better than, for example, covalent nonmetals)
  • Although there is some reactivity in the heavier ones, the noble gasses are still strikingly less reactive than the rest of the nonmetals - and than all other elements.

This is my best attempt at explaining the reasoning that led the four of us to agree to subcategorize the nonmetals into "reactive nonmetals" and "noble gasses". What remains now is

  • Corrections and additions to my explanation, as I'm sure I've missed some of this.
  • The path forward to gain consensus amongst the broader WP community.

Please feel free to make any corrections or additions necessary. YBG (talk) 05:15, 18 October 2017 (UTC)

  • I suggest we refrain from an RfC and keep this particular categorization problem within our project, at least for the time being. We've had three RfC I can remember: on what group 3 is composed of, on the color of group 12, and the previous attempt to establish a nonmetal coloring. The first two are good problems that are commonly disagreed on outside WP and both have clear-cut alternative solutions (either -La-Ac or -Lu-Lr, either TM or PTM, there's no possible third alternative in either case), so people do understand what they'retrying to get. I am no particular supporter of the group 3 RfC outcome, but an RfC was very appropriate for the problem in hand. In contrast, now we have a problem without a well-defined set of alternatives. We could start an RfC if we needed any alternatives to consider but we do have one we want to implement. It appears to me that nobody currently confronts the suggested outcome, so we don't need an RfC for external mediation. And, most importantly, we as a project are free to go bold and try it out. If there is opposition, we can start an RfC for the said mediation.
I get it that it may look like I'm finally getting what I've wanted and trying to make it happen already, but the fear that we may never get anything approved in a non-multiple-choice problem like ours other than by chance is genuine. This is exactly the idea I've had since the previous RfC on this problem.--R8R (talk) 08:23, 18 October 2017 (UTC)
(ec) re R8R
I'm not (yet) saying we should skip RfC. While I'm OK with this summary/proposal, I think we should also thoroughly check it against all comments made in the recent RfC on this same issue. While some opponents are to the point (I myself read them mainly as WP:FRINGE arguments), other arguments were outside the topic but they did not conclude as being discarded, and they still look like bad !votes for any outsider formally concluding the RfC. I think this is one of the problems with an RfC that R8R described. So what does RfC say about/against this current summary/proposal? IMO:
Removing the diatomic and polyatomic subcategories as step one: generally accepted (i.e., reject these categories), as they as "not common in chemistry". This while they are stronger wrt defining borders (less fuzzy border issues) than the RfC categories are.
Our 'right' or audacity to categorize, even where IUPAC does not tread (that is, the categories with non-fixed member lists, mainly in the p-block): allowed. IMO, "being useful" is not the most important check for encyclopedia, but "correct" (sourced, no OR) and "commonly used" (not FRINGE, not OR) are. This allows categorising by supercategories and main chemistry classifiaction metal–metalloid–nonmetal, and their subsequential subcategories, being complementary with recognised fixed-list subcategories (so that "nonmetals minus the noble gases" too implies a category). Also, this keeps up the full covering and trend showing of the periodic table.
As for names of the categories: where no name is commonly accepted and used, we can correctly introduce descriptive class names (as is "reactive nonmetals"). In a complete-covering scheme, these names can be relative ("nonmetal", while referring to and depending on "metal" is acceptable). I would not limit the scheme with requirement "we should limit ourselves to two words [for new, descriptive names]", but since "reactive nonmetals" is found to be OK, this is moot. Under no circumstance a categorisation may be discarded because of not having an appropriate name available.
As for the new category proposed, as content: IMO it has enough general acceptance in science & common chemistry, together with its complementary well-defined categories "noble gases" and "nonmetals". As said, border issues (mainly with the metalloids) are acceptable in the covering scheme.
Did I miss sound counter-arguments mentioned in the RfC?
In general, and as a reply to the R8R suggestion, we should be stronger in pushing our 'right' to categorise, inside or outside an RfC. -DePiep (talk) 09:13, 18 October 2017 (UTC)
  • Support -- Sandbh (talk) 08:58, 18 October 2017 (UTC)
  • As color for the new category, I suggest using the new greenish one, not yellowish. Yellow has more issues with white background and such. All else: same.
   Reactive nonmetal → #A1FFB4 
Should be applied to #Scheme IV then. Yellow will not reappear in the big scheme. -DePiep (talk) 23:06, 24 October 2017 (UTC)
  • Question for @Double sharp and R8R:: what would you !vote in this proposal? You opposed the RfC (R8R: "I think "active nonmetals" is a poor term", Ds: "If the proposed classification is not going to be as well-received by chemists as the current one"). I think this round-up overview is a good point to indicate chances of survival. -DePiep (talk) 20:55, 31 October 2017 (UTC)
  • Support. Double sharp (talk) 06:52, 1 November 2017 (UTC)
  • Support.--R8R (talk) 07:51, 1 November 2017 (UTC)

Standard atomic weight[edit]

I've listed the standard atomic weights central: {{Infobox element/symbol-to-saw}}. Also for most stable isotope (when no s.a.w. exists): {{Infobox element/symbol-to-most-stable-isotope}}. This helps control correct number & formatting throughout.

By now, we should be familiar (actually, I'm happy that I am, at last ;-) ) with the variant values that IUPAC (CIAAW) publishes for each element. That is, next to the formal s.a.w. (often a long number, and possibly an interval), the element may also formally have an abridged and a conventional value. The resulting short number value I started naming "formal short" here.

Please check {{Periodic table (18 columns, large cells)}}, as it now mentions two values. OK?

Over at Wikidata, things are a mess (see this comparision). WD 'must' have a mass unit, so they've added "u" (by recalculation); they've used PubChem as a source which has way different numbers, it is a mixup of long and short numbers. (One wonders what molecular weights are worth, when calculated by PubChem). Anyway, I'll start a talk over there. -DePiep (talk) 13:23, 8 October 2017 (UTC)

Looks good – except that I think we should define that values encased in square brackets are the mass number of the most stable isotope, not the nonexistent standard atomic weight. Double sharp (talk) 13:27, 8 October 2017 (UTC)
Yes. On my todo-list. See also {{Periodic table (standard atomic weight)}}. -DePiep (talk) 13:41, 8 October 2017 (UTC)
Numbers & values are clarified here. For starters, it's a 3×3 table. (Then add m.s.i. ...). -DePiep (talk) 20:41, 8 October 2017 (UTC)

CIAAW 2017[edit]

It is November 2017, and as far as I can see IUPAC's CIAAW has not announced or published any change in their standard atomic weights (Ar, standard). FYI, any definite changes in their s.a.w. values are published biannually (2013[1], 2015: Yb changed), so 2017 is open and 2019 will be the next opportunity. -DePiep (talk) 22:54, 6 November 2017 (UTC)


Cool periodic table colouring: Where the elements come from[edit]

We have talked about diagonal shading before. Nothing ever came of it. I saw this table and thought the diagonal shading was quite effective. Goodness knows the nonmetal saga will keep me going for a while but I thought this table was noteworthy.

08:51, 18 October 2017 Sandbh
Cool – though I think Tc, Pm, Po–Ac, Pa, Np, and Pu should be listed as a separate category "from decay". Then maybe we could put Am–Og on the table as "Humans". ^_^ Double sharp (talk) 02:53, 21 October 2017 (UTC)
Apart from showing the cells being double or triple colored, should not this history (where does an element come from?) be rewritten, or at least expanded with a new topic? The current primordial etc. approach is Earth-centric. This graph says there are six origins, plus grey and human. -DePiep (talk) 09:01, 25 October 2017 (UTC)
Not really. Stars produce some of everything; there is probably some oganesson in the mess that results from the r-process. It just doesn't stay oganesson for very long, so the breakdown is itself stuck to primordial elements only. (The short-lived daughters of Th and U should really be greyed out as from decay.) Double sharp (talk) 11:54, 25 October 2017 (UTC)
  • Back to what the OP wants to say: combined colors, diagonally, look good.
Yes, and we could work on that - later on. However, wrt graphical presentation, important is: in our general PTs, we present multiple themes, like: Z, symbol, category, atomic number, SoM, occurrence (and this is the small PT; wall-size PTs also have atomic weight, elconfig, oxidation states). The diagonal coloring in the OP's PT is nice and effective, because it only has one theme (with six colors only, how easy that is ;) ). For inspiration, graphical abundance: [1] (from [2]). -DePiep (talk) 19:53, 8 November 2017 (UTC)

New article by Eric Scerri on the periodic table[edit]

How Should the Periodic System be Regarded? A brief look at some published proposals. Sandbh (talk) 03:48, 25 October 2017 (UTC)

It seems to me that you can look at the PT either as explanatory or as descriptive, or maybe as both. It not only tries to describe the commonalities we see between the elements, but also be founded on an explanation why they should show these commonalities at all – which inevitably goes back to the relationship between observed electron configuration and observed chemistry. If we are basing the table on observed chemistry, as we should, then idealised electron configurations never actually enter into it.
I do not think we can press very much further: the Madelung rule only explains things as much as the original version of periodicity. It notes the pattern in shell-filling, but we are left rather in the dark on why it should happen that way, and what's more, actual calculations show something a bit more complicated. In Cs and Ba, 6s is below 4f and 5d; but 5d drops down in energy and collapses at La, whereas 4f only does so at Ce. This is probably my main point when I argue for Sc-Y-La-Ac. If we discover a deeper truth that explains this ordering from more fundamental principles, it would be more comfortable to go further. But while this goal of reductionism is good, it doesn't do us much good to reduce down to foundations we're not even sure of, and we must keep in mind what we are reducing from. Double sharp (talk) 08:46, 25 October 2017 (UTC)
Interesting (actually: WOW!). Is Scerri following & feeding our discussions? ;-) Thx for linking. -DePiep (talk) 00:56, 8 November 2017 (UTC)


I think the wiki talk page on aluminium needs a little attention. There might be the chance that two of the more productive editors of the project would need a calm voice and a cup of tea. The topic itself would be a topic for the whole project. --Stone (talk) 20:22, 26 October 2017 (UTC)

Compounds in element articles?[edit]

As discussed at Talk:Aluminium#Move the history of alum to .......

The issue is how element-focused should the content be in an article about an element. Into aluminium, user:R&R has inserted a long and elaborate history of alum. This well intentioned (but IMHO misguided) editor has decided that alum merits a special place in appreciating aluminium. I think that the history of alum belongs in alum. And furthermore that, ordinarily, extended discussion of individual compounds should not be part of any element article. To illustrate what could happen: in hydrogen, one could write huge sections on methane, water, ammonia, all arguably far more significant that alum. Adding large sections on methane, water, ammonia would bloat an already large article. The debate is about policy really, and I hope that this project can arrive at consensus and guide future editors with advice. Thank you, --Smokefoot (talk) 21:11, 26 October 2017 (UTC)

I have clearly agreed we should not focus on methane, water, or ammonia in hydrogen. The point is not in importance, the point is in relevance. I insist that the aluminium situation is different and I have explained the difference; as I have noted in response to Stone, this part of the article will not remain as long after the section is complete.
Policy-wise, I have to note we have articles on chemical elements, not simple substances formed from those. We discuss elements (as opposed to simple substances) in some other sections: Chemistry, Occurrence, Toxicology. (Physical properties remain restricted to the simple compound because the section would become too long and difficult to write otherwise because of the multitude of the possible compounds; same applies to Production.) I do find that while the simple substance takes some precedence in the matters of History, there is no particular reason to abandon all historical information on compounds. We could use information on compounds if those compounds have had some importance on discovery of the simple substance, for example. I wouldn't want to lose the information on fluorspar being flux (which is even the reason why fluorine is called so). People used fluorspar and then they wanted to see what it was made of; that's a part of history of fluorine. I wouldn't want to lose the (shortened) history of alum (which is the reason why aluminum is called so). People traded alum and then they wanted to see what it was made of; that's a part of history of aluminum. I wouldn't want to lose the mention of salt in chlorine; and so on. This is all a part of histories of chemical elements.--R8R (talk) 22:32, 26 October 2017 (UTC)

Glass definition[edit]

A little off topic but it has merit in proposing a definition for the general reader, and one for the expert. From the article in question:

A modest proposal to update the textbooks
The new proposed definition of glass for non-specialists is:
‘Glass is a non-equilibrium, non-crystalline state of matter that appears solid on a short time scale but continuously relaxes towards the liquid state.’
The two materials scientists also have a more detailed definition for experts:
‘Glass is a non-equilibrium, non-crystalline condensed state of matter that exhibits a glass transition. The structure of glasses is similar to that of their parent supercooled liquids (SCL), and they spontaneously relax toward the SCL state. Their ultimate fate, in the limit of infinite time, is to crystallise.’

-- Sandbh (talk) 05:52, 31 October 2017 (UTC)

On the placement of hydrogen and helium in the periodic system: A new approach[edit]

I couldn't find a free copy of this article but was able to access it via this link.

Scerri has commented on this article, here: A Comment on the Srivaths - Labarca Periodic Table. It's the sixth pdf link down the page. See also the fifth link down, for a commentary in the same journal. And see also, the first link on this page.

Here's another commentary: On the 'true position' of hydrogen in the periodic table. There is a picture of the new approach PT at page 87 (and note the PTM being referred to as basic metals, page 86).

-- Sandbh (talk) 06:38, 31 October 2017 (UTC)

Helium fairly obviously should go over neon, unless you are making a single point to the exclusion of all others. If you want to force H into any group, group 1 works the best (I've expounded upon why at length in the archives), though I am in great sympathy with Kaesz and Atkins' proposal to float it over the table. As the last commentary says, just because H is floating doesn't mean that periodicity doesn't apply to it. After all, initial cases are often exceptional, and normal behaviour is more often described by limiting behaviour. ^_-☆ Double sharp (talk) 15:17, 31 October 2017 (UTC)

Large edits in the theoretical elements[edit]

User:Ysku is making large, good faith edits in the theoretical elements area and PTs (Special:Contributions/Ysku). I'm not sure all are strong improvements. Pls take a look. -DePiep (talk) 20:05, 6 November 2017 (UTC)

I recall there was a consensus in this project once to abstain from creating articles on elements beyond 121 (or was it 122?) for as long as we don't have too much predicted data. Personally, what I think makes an element notable is an actual attempt to create it because that would be actual non-trivial data and predictions in this area, as I recall, are indeed fringe and cannot be the sole reason to have an article. I would personally be very interested to see any proof of the claimed attempt to synthesize element 123 from lawrencium; if nothing shows up, I think we should delete the article for the time being by any measure.--R8R (talk) 21:03, 6 November 2017 (UTC)
It looks like all Ysku has done is bring together all the stuff, including the deleted, wrong stuff, from all the previous versions of the article he could find, so I have turned them back into redirects. IIRC when we had the consensus, we set the limit at 120, but since then enough papers have come out for 121 that I felt okay recreating it this April or May. I still haven't found much substantial for 122, or anything at all for 123 and up, but I still keep a list of sources at Talk:Unbibium like I had at Talk:Unbiunium. And in the meantime I am rooting for the next attempts from the JINR and RIKEN to hit 119 and 120, which is basically a prerequisite before predictions of 123 and up can really be taken seriously. Double sharp (talk) 06:55, 8 November 2017 (UTC)

RfC: remove Respell (pronunciation) from Infobox element[edit]

Add Term symbol to the Infobox?[edit]

Here is a proposal to add term symbol to {{Infobox element}}, below the electron configuration. -DePiep (talk) 20:31, 8 November 2017 (UTC)

Resdesign of Infobox PT group[edit]

Today, {{Infobox periodic table group}} is a wikitable construct. I have rebuild that into using {{Infobox}} (in /sandbox). Also, serious design changes are to be considered. For example: improve group overview data (think: header), reduce individual element data, only add data that has group-related (periodic) meaning, and present that as such (how to?). See current demo's at /testcases (including alkali fireworks!).

Please join in at Template talk:Infobox periodic table group#Redesign of Infobox PT group. -DePiep (talk) 13:50, 14 November 2017 (UTC)