Talk:Nonmetal

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Good article Nonmetal has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
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Question[edit]

Are the noble gases classified with the nonmetals? Periodic table/Metals and Non Metals says yes, but I don't really see why. They break the periodicity pattern of increasing electronegativity; they might as well be placed to the left of the alkali metals as to the right of the halogens. -Smack 20:46 20 Jun 2003 (UTC)

"Non-metal" is a pretty woolly, general term, but noble gasses tick about 90% of its boxes.--feline1 16:13, 15 January 2007 (UTC)

Abundance of non-metals, how come?[edit]

The article says "Only eighteen elements in the periodic table are generally considered nonmetals, compared to over eighty metals, but nonmetals make up most of the crust, atmosphere and oceans of the earth. Bulk tissues of living organisms are composed almost entirely of nonmetals."

First thing I wondered about, if the large majority of elements in the periodic table are metals, how come they are so prevalent on Earth and in (Earth-based) life?

I was reading the article on Metal first, and figured the definition was very inclusive, so I clicked through here to find the properties of non-metal, since they are so common in life, I wondered what makes them special. Does anybody know? And care to write it up in the article?

Infobag (talk) 12:45, 26 May 2010 (UTC)

Metallicity of carbon[edit]

Why is carbon a non-metal if it has metallic allotropes?

What do you mean? Graphite conducts electricity but it's not generally considered "metallic". —Keenan Pepper 22:33, 20 May 2006 (UTC)
Graphite is a bit metalloid, perhaps. All these things are shades of grey. It doesn't really matter! They're just useful terms and concepts, not rigid laws.--feline1 16:13, 15 January 2007 (UTC)

Graphite conducts electricity, but it does it in a different fashion than metals do. It has unbonded electrons which are not part of a metallic bond. This is why it is a better conductor the hotter it gets, whereas metals tend to be poorer conductors when hot. So it is a conductor but not due to metallic properties.

Graphite is defintely not a nonmetallic substance. It has very high melting and boiling point, its electrical and thermal conductivity is far much more similar to metallic than nonmetallic. In ddition it is metal-like looking and grey in pure form. Graphite itself passes better to metalloids, not to nonmetals. The same is true to black phosphorus and grey selenium. Iodine also looks like a metalloid, not like a nonmetal. Carbon exhibits borderline metalloidl and nonmetallic properties, such as phosphorus and selenium. I think that it is better when C, P and Se (not only Se) are marked as "half-nonmetals" and "half-metalloids".

Terms such as "alkaline earth metal", "polyatomic nonmetal", "diatomic nonmetal", "halogen", "noble gas" do not indicate metallic character. Beryllium is a meta-metal (metallic element with some mrked (chemical) metalloidal properties), but not a metalloid (such as aluminium). Sulfur is polyatomic nonmetal, but its level of metallicity is much more similar to iodine, a "diatomic nonmetal", not to other polyatomic nonmetals (C, P and Se). Radon (monoatomic nonmetal) and hydrogen (diatomic nonmetal) are more metallic than fluorine (diatomic nonmetal). I think that division to six metallicity classes could be better:

  • "strong" metals (such as Na, Fe),
  • meta-metals (such as Be, Al, Ga, Sn, Pb, Bi, Po),
  • metalloids (intermediates between (meta-)metals and nonmetals)(such as B, Si, Te),
  • semimetalloids, half-metalloids (intermediates between nonmetals and metalloids) (such as C and Se),
  • "weaker" nonmetals ("half-semimetalloids") (such as H, S, Rn),
  • most typical nonmetals (such as O, F, Cl, Ne, Ar, Kr).

79.191.185.122 (talk) 14:34, 8 November 2013 (UTC)

Well, I like it. You'll need to explain how to distinguish between strong metals and meta-metals, and how to distinguish between the weaker nonmetals and the typical nonmetals. You'll also need to supply supporting references. Sandbh (talk) 02:52, 10 November 2013 (UTC)

Maybe a division of eight classes would work:

   
Noble gases
He, Ne, At, Kr, Xe, Rn
   
Strong metals
EN < 1.4
Strong nonmetals
O, F, Cl
Typical metals
most TMs
Typical nonmetals
N, S, Br
Poor metals
Ga, Bi etc
Near metalloids
H, C, P, Se, I
Metalloids
B, Si, Ge, As, Sb, Te

Notes

1. The noble gases and the metalloids are at the opposite ends of the clock. Noble gases have the valence shell configurations that metals and nonmetals aspire to. Metalloids are stuck in the twilight zone.

2. Among the near metalloids, H has the physical properties of a nonmetal but acts chemically like a metal; C, P, Se and I look like metals but act chemically (mostly) like nonmetals.

3. The typical nonmetals comprise a gas, a solid and a liquid.

4. This division is close to the current categories. Alkali metals, alkaline earths, lanthanides and actinides ≈ strong metals; TMs ≈ typical metals; poor metals = poor metals; metalloids = metalloids; polyatomic nonmetals ≈ near metalloids; diatomic metals ≈ typical nonmetals and strong nonmetals; NG = NG. Sandbh (talk) 11:14, 13 November 2013 (UTC)

Division looks quite good! The least typical of "typical nonmetals" is sulfur of course, but has less metalloidal properties than near-metalloids. Can polymeric (non oligomeric, such as octasulfur) sulfur be stable at STP? At higher temperatures sulfur is more "metalloidal" because it polymerizes and changes color to brown-black. Plastic sulfur has low stability and it crystalizes to common, highly nonmetallic form. Hydrogen not always acts like a metal, it can acts like a metal and like a nonmetal. But hydrogen's chemical behavior is clearly strange for a typical nonmetal.
C, P and Se are "polyatomic near-metalloids" and I and H "diatomic near-metalloids". Compounds such as water or HF, HCl have also really relatively high boiling points when we compare their molar masses to their boiling points in Kelvin scale. Near-metalloids can be marked by stripping.
And Au, Pt and (most probably) Cn are also really poor metals.
95.49.248.226 (talk) 00:31, 17 November 2013 (UTC)
Thank you. If we actually did something like this I wouldn't bother with the categories of polyatomic nonmetal and diatomic metal. There would only be the categories of near metalloid; typical nonmetal; and strong nonmetal. Au and Pt are not poor metals. They are nowhere near that: see here. Au has many nonmetallic properties but is still regarded as 'king of the metals'---there are zero mentions in the literature, as far as I know, of Au being referred to as a poor metal or the like. Same goes for Pt. Sandbh (talk) 01:11, 17 November 2013 (UTC)

Au and Pt are physically good metals, but chemically they are not good metals. (Typical) poor metals are low-melting, soft and have quite high electronegativity. Their chemistry is metalloidal in some way, even at low oxidation states. Group 12 elements also have domination of poor metal characteristics. Pt and Au present some sort of regression of metallic chemical properties. Be is chemically poor metal, but physically is really good. Situation of Al is similar.

95.49.248.226 (talk) 12:15, 17 November 2013 (UTC)

In German Wikipedia selenium is considered a metalloid, but phosphorus and carbon unjustly not[edit]

In German Wikipedia selenium is considered metalloid, but carbon and phosphorus are equated to fluorine and oxygen in metallicity (C and P are named as just nonmetals). Selenium is marked as half metalloid and half nonmetal in periodic table template in German Wikipedia. Carbon and phosphorus should be named as metalloids if selenium is named so. All "diagonal carbon group" (C, P, Se, I, even Rn which have some cationic behaviour) exhibits intermediate proprties between typical nonmetals and typical metalloids ("diagonal boron group", especially: B, Si, As and Te). I think it is "unjust" when selenium is named as metalloid and carbon and phosphorus "only" nonmetals. Phosphorus have lower electronegativity than Se and C and should be also named as "weak metalloid". Ionic sodium selenide (similar to oxide of Na, easily reacts with water) and telluride (highly soluble in water). Black phosphorus have much higher melting point (about 600 C) than gray selenium. Very hard to melt, grayish-black lustrous graphite which is better conductor of heat and electricity (often used in electrodes, such as harder glassy carbon) than many metalloids at normal conditions definately does not fit to nonmetals, but to metalloids (semimetals), such as gray selenium and black phosphorus. Naming selenium as (half)metalloid and classifying carbon and phosphorus as only nonmetals is even flawful and should not be used. Even insulating and transparent diamond (less metallic than graphte form of carbon) is not so much like other, typical nonmetallic elements (density compared to atomic mass, heat conductivity, melting point, hardness - they are associated with metals (especially heavy), but diamond is in it better than all examined metals! (paradox)). It is rather like compound of metal and nonmetal like aluminium oxide, which can also be very hard. — Preceding unsigned comment added by 95.49.86.160 (talk) 22:37, 11 October 2013 (UTC)

Carbon[edit]

Carbon actually has a higher melting and boiling point than any metal, right? Boron is pretty much up there also. I do not think melting and boiling point is much of a guide for determining metals vs nonmetals.

nani na muni —Preceding unsigned comment added by 120.56.168.4 (talk) 05:12, 8 May 2010 (UTC)

Carbon high melting point and other not-nonmetallic traits in its allotropes does not make it more metallic than "diagonal boron group", but it should not be included in less metallic group than toxic and forming more acidic hydride than sulfur hydride element with atomic number 34. 95.49.86.160 (talk) 22:55, 11 October 2013 (UTC)

Phosphorus not less metallic than selenium[edit]

Se, P and C are in the same level of metallicity. They can be marked as "half-metalloids" and "half-nonmetals". Phosphorus has even lower electronegativity than some heavy metals (such as gold) and black phosphorus is a metalloid which has higher melting point (about 600 C) than less metallic elements and its hydride is not acidic like hydride of sulfur, ("infamous") selenium and even typically metalloidal tellurium! Black phosphorus is, in addition, the most thermodynamically stable form of element number 15. Not this low-melting whitish waxy poison known as tetraphosphorus. Metalloid arsenic also has highly nonmetallic allotrope (unstable and really light yellow arsenic), but main form of As has even better electrical conductivity in normal conditions than manganese. Phosphides are also often quite metallic, they are similar to arsenides.95.49.86.160 (talk) 22:55, 11 October 2013 (UTC)

My periodic table showing the metals and nonmetals[edit]

User:Wd930/Periodic table/Metals and nonmetals
Hydrogen is not on top of lithium here because it is a nonmetal. —Preceding unsigned comment added by Wd930 (talkcontribs) 05:30, 3 December 2010 (UTC)

A metallic allotrope of carbon has been hypothesized to occur at 1.1 THz.[edit]

Is it correct to specify THz? I would have thought that pressure (GPa?) rather than frequency (THz) would be determinative. TomS TDotO (talk) 14:47, 5 June 2012 (UTC)

No it is not correct to specify THz. The reference cited even states TPa. 192.75.48.150 (talk) 17:49, 27 July 2012 (UTC)

Even highly nonmetallic oxygen forms metallic form at very high pressure, which can also be a superconductor. Even at lower pressure than more metallic carbon!

http://en.wikipedia.org/wiki/Solid_oxygen#Metallic_oxygen

A ζ-phase appears at 96 GPa when ε-phase oxygen is further compressed. This phase was discovered in 1990 by pressurizing oxygen to 132 GPa. The ζ-phase with metallic cluster has been known to exhibit superconductivity at low temperature. 95.49.86.160 (talk) 23:01, 11 October 2013 (UTC)

GA Review[edit]

Toolbox

See WP:DEADREF
for dead URLs

This review is transcluded from Talk:Nonmetal/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Adabow (talk · contribs) 06:47, 19 August 2013 (UTC) GA review – see WP:WIAGA for criteria

  1. Is it reasonably well written?
    A. Prose quality, no copyvios, spelling and grammar:
    B. MoS compliance for lead, layout, words to watch, fiction, and lists:
  2. Is it factually accurate and verifiable?
    A. Has an appropriate reference section:
    B. Citation to reliable sources where necessary:
    C. No original research:
  3. Is it broad in its coverage?
    A. Major aspects:
    B. Focused:
  4. Is it neutral?
    Fair representation without bias:
  5. Is it stable?
    No edit wars, etc:
  6. Does it contain images to illustrate the topic?
    A. Images are tagged with their copyright status, and valid fair use rationales are provided for non-free content:
    B. Images are provided if possible and are relevant to the topic, and have suitable captions:
    superb use of images and diagrams
  7. Overall:
    Pass or Fail:

I will review this article over the next few days. I have gone over the images; all are free and used well. Adabow (talk) 06:47, 19 August 2013 (UTC)

Prose/MoS quibbles[edit]

  • I have been doing some minor copyediting; feel free to undo any and all of my edits.
Adabow 07:22, 19 August 2013 ([1] sign added. -DePiep (talk) 08:58, 19 August 2013 (UTC))
  • "Chemically, the nonmetals have relatively high ionisation energy and high electronegativity;" - should ionisation energy and electronegativity be pluralised?
    • X mark.svg Not done Since it's referring to ionisation energy and electronegativity values, I don't think it needs to be pluralized. Double sharp (talk) 13:54, 20 August 2013 (UTC)
  • The overview part of the "Categories" section could do with some more liberal linking
    • X mark.svg Not done I looked through it. I tried. I really tried. But I really don't see any terms there that aren't already linked elsewhere (well, except metallic bonding, which I have now linked). Could you point me to some terms there that you would like to see linked? Double sharp (talk) 13:54, 20 August 2013 (UTC)
  • Is the boldfacing of 'noble gas' warranted? Done
  • "all known in polymeric forms" is ambiguous: it could mean "all potential oxides are known, and are in polymeric forms" or "all known oxides are in polymeric forms" Done Sandbh (talk) 00:57, 21 August 2013 (UTC)
  • In 'Abundance and extraction', several elements are mentioned which are not previously mentioned, and should therefore be linked. Done

These are all minor nitpicks; nothing here fails to meet the first criterion. Adabow (talk) 21:52, 20 August 2013 (UTC)

Referencing[edit]

  • Excellently referenced, with a large number of sources. Inline citations where appropriate. Adabow (talk) 21:52, 20 August 2013 (UTC)

Breadth[edit]

  • I think that in the 'Polyatomic nonmetals' section the vast discipline of organic chemistry should be mentioned in a sentence. Perhaps after the sentence describing the tendency for polyatomic nonmetals to catenate? Adabow (talk) 21:52, 20 August 2013 (UTC)
Done Sandbh (talk) 00:19, 21 August 2013 (UTC)

Neutrality[edit]

  • No bias or POV statements. Adabow (talk) 21:52, 20 August 2013 (UTC)

Stability[edit]

  • No recent edit warring or talk page disputes. Adabow (talk) 21:52, 20 August 2013 (UTC)

Media[edit]

  • There are some fantastic images here, and there are used and captioned well. All are free. Adabow (talk) 21:52, 20 August 2013 (UTC)

Overall[edit]

I would like to see a mention of organic chemistry, as it is fundamental to the chemistry of carbon.

A shrewd and fundamental (to life as we know it) observation. Will do. Done Sandbh (talk) 00:17, 21 August 2013 (UTC)

Otherwise, this is an excellent article. I will place the review on hold for now. Adabow (talk) 21:52, 20 August 2013 (UTC)

Thank you. Sandbh (talk) 22:30, 20 August 2013 (UTC)

Now that Sandbh has added this, I will pass the article. Great work and well done to everyone involved; keep it up! Adabow (talk) 00:22, 21 August 2013 (UTC)

Timely and incisive review. Much appreciated. Sandbh (talk) 01:01, 21 August 2013 (UTC)

Better division[edit]

I think that division of nonmetallic elements to semimetalloids, (typical) nonmetals and noble gases (helium group elements, HGE) is better than currenly used division to polyatomic nonmetals, diatomic nonmetals and noble gases.

Sulfur (polyatomic nonmetal) is less metallic than iodine (diatomic nonmetal). Iodine belongs to diagonal carbon group, sulfur to diagonal nitrogen group. Sulfur has lower conductivity of electricity and heat than iodine, sulfur looks nonmetallic, but iodine looks greyish and has metal-like luster. It means that iodine has to be named as more metallic than sulfur.

Semimetalloids (C, P, Se, I) are significantly more metallic than nonmetals on the right of then, but less metallic than typical metalloids on the left side of periodic table. Most stable form of semimetalloids appear as greyish(-black) solid with lustre similar to metals (graphite, black phosphorus, grey selenium, crystalline iodine), unlike main forms of nonmetals. They are also better electrical and thermal conductors (it is significantly less marked it the case of iodine). Lighter semimetalloids have higher melting point than heavier (graphite >> black phosphorus > grey selenium > iodine). Carbon has also some similarities to silicon and boron (very high melting point, formation of hard allotropes (glassy carbon (7 Mohs), diamond (10 Mohs), carbides, borides and silicides are often very hard, names of these three elements end at "-on", carbon has less metallic properties, because it lies more to the right (belong to carbon diagonal group, not to boron diagnonal group, such as silicon)).Phosphorus has the lowest electronegativity in Pauling scale from all of them, it is quite similar to metalloid arsenic, maybe even more to nonmetal nitrogen. White phosphorus deforms view on metallicity of phosphorus. In addition, black ("metallic") phosphorus is the most stable allotrope of this element. Phosphorus (gaseous elements: hydrogen and radon also) have lower electronegativity than some heavy metals, especially gold. Phosphorus also have significally lower electronegativity than carbon, selenium and iodine.

Solid bromine does not exhibit metallic luster and is even rather transparent:

http://www.periodictable.ru/035Br/Br_en.html — Preceding unsigned comment added by 95.49.94.63 (talk) 12:59, 24 October 2013 (UTC)

95.49.94.63 (talk) 13:01, 24 October 2013 (UTC)

A few things:
Hydrogen is not a typical nonmetal. You'll need to come up with a better name than 'typical' nonmetals.
Don't call them semimetalloids, unless you can find some references in the literature supporting the use of that term. There are no sources in the literature that I know of that categorise these elements as semimetalloids. The closest there is is 'near metalloid' for C, P and Se.
S and I are not that clear. By my reckoning, and for the following fifteen properties: first ionization energy; electron affinity; standard reduction potential; melting point; boiling point; liquid range; most stable oxidation state; ductility or malleability; appearance; Goldhammer-Herzfeld metallicity ratio; band gap; conductivity; and cationic chemistry, S is ahead of I on 9 properties, with one (cationic chemistry?) a tie.
If you'd like to propose a revised division of the nonmetals, here are the criteria (they are known as the 'YBG criteria', after the editor who invented them) you'll need to satisfy:
  1. Clear. The criterion for division should be easily explained
  2. Unambiguous. It should be (relatively) obvious which category each element fits into
  3. Meaningful. The categories should have significance more than just dividing for the sake of dividing. There should be enough within-group similarity and enough between-group dissimilarity so that each group could be the subject of a separate encyclopedia article.
The current division of the nonmetals into polyatomic, diatomic and monatomic meets these criteria.
Feel free to go ahead and do your research and compile a table of the properties of semimetalloids, 'typical' nonmetals, and noble gases, supported by references, and see if you can meet the criteria set out above.
Good luck. Sandbh (talk) 03:38, 9 November 2013 (UTC)