|Periodic table is a featured article; it (or a previous version of it) has been identified as one of the best articles produced by the Wikipedia community. Even so, if you can update or improve it, please do so.|
|This article appeared on Wikipedia's Main Page as Today's featured article on February 28, 2004.|
|The content of Placement of lanthanides and actinides in the periodic table was merged into Periodic table. For the contribution history and old versions of the redirected page, please see ; for the discussion at that location, see its talk page.|
|Periodic table has been listed as a level-3 vital article in Science. If you can improve it, please do. This article has been rated as FA-Class.|
|This article is of interest to the following WikiProjects:|
|This article uses British English with IUPAC spelling (realize, aluminium, sulfur, and caesium), and some terms used in it are different or absent from other varieties of English. According to the Wikipedia and WikiProject Chemistry style guides, this should not be changed without broad consensus.|
|Threads older than 60 days may be archived.|
recolour group 12 as post-transition metals?
|“||My impression has been that (a) authors who show 3–11 give sound reasons for excluding group 12, whereas (b) authors who show 3–12 either say nothing and hope nobody raises a hand at the back of the class, or they offer weaker or superficial reasons for including group 12.
Cotton et al., recently a US standard, are an example of (a). They define transition elements as those having partly filled d shells, which covers groups 3–10, plus those that have partly filled d shells in any of their commonly occurring oxidation states, thereby including group 11 (Cu, Ag, Au). The group 3 elements are counted as transition metals, but since the properties of these metals are "quite different" from those of the regular d-block elements, they are treated, on chemical similarity grounds, in the chapter on the lanthanides. The group 12 elements (Zn, Cd, Hg) are treated as main group metals, since none of these elements give rise to compounds in which d electrons are lost.
Greenwood and Earnshaw are an example of (b). They write that the d-block elements (groups 3–12) are commonly described as "transition elements". On the group 3 elements they note that, "although each member of this group is the first member of a transition series, its chemistry is largely atypical of the transition elements." On the group 12 elements they comment that, "in view of the stability of the filled d shell, these elements show few of the characteristic properties of transition metals despite their position in the d block of the periodic table." They add that zinc resembles transition metals in forming complexes; cadmium is "rather similar" to zinc; and that many compounds of mercury (and cadmium to a lesser extent) are highly coloured, which is a characteristic of transition metals.
Since the literature is roughly divided on this point, and we need to go one way or t'other in colouring our table, it appears preferable to occupy the arguably stronger ground of 3–11 rather than the dubious ground of 3–12.
I don't mind treating Sc-Y as (incipient) transition metals. The addition of the d-electron confers transition metal physical properties, as noted by Greenwood and Earnshaw, and that's good enough for me in terms of periodicity. OK they don't display hardly any of the characteristic chemical properties of transition metals. I can live with that since it provides an illustrative contrast with the group 4–11 transition metals and shows the chemical influence of d electrons (in addition to the impact on physical properties.
Towards the other end of the d block, are the group 11 twilight zone transition metals and their capacity to demonstrate both transition metal chemistry and main group chemistry. Effectively, they can also be regarded as incipient main group metals.
Of course, by the time we get to group 12 there is no d-block chemistry, and there is no d electron cohesion contribution to physical properties, as demonstrated by the abrupt and significant reduction in melting and boiling points in passing from group 11 to group 12.
The reported synthesis of HgF4 carries near enough to zero weight, given (if it really does exist) it would represent something on the order of one-millionth of the chemistry of mercury, and even then at only a few degrees above absolute zero.
In our transition metal article I'd be inclined to still discuss the group 12 elements, at least for comparative purposes (presuming they were colour categorised as PTMs).
In conclusion I'd support group 12 as post transition metals on the grounds of superior chemical and physical arguments.
The fact that IUPAC's Gold Book definition follows Cotton is another point in favour of this classification. Yes, we have been known to disregard IUPAC when common usage suggests otherwise, but this issue tends to be split 50–50 between textbook authors. What pushes me finally over the line to removing group 12 from the transition metals is that people who include them in the transition metals proper generally have to point to lame arguments to keep them in. Group 12 just does not show either the chemical or physical properties of transition metals, whereas groups 4–10 show both, group 3 (including the lanthanides and actinides) shows the physical properties, and group 11 shows the chemical properties.
We can of course cover the differing conceptions of what a transition metal is in Wikipedia when the issue is relevant. However, it seems to me that the best way to go as a default is to give the classification that is most representative of an element's chemistry (that's why we don't colour lanthanum as a transition metal, for example). Thus I think it is better to colour Zn, Cd, Hg, and Cn as post-transition metals.
- If you wish to comment, please go to WT:ELEM § A less extreme proposal -- YBG (talk) 04:24, 30 November 2016 (UTC)
Image updating for new named elements
The image under the section "First systemization attempts" is not up to date, still using placeholder names. If someone could put a updated image there it would be greatly appreciated. — Preceding unsigned comment added by Fig28awsome444 (talk • contribs) 02:36, 2 December 2016 (UTC)
Is there a reason why 12 letters of the ABC are not used in the Periodic table? A,D,E,G,J,L,M,Q,R,T,X,Z
- Aluminium - A
- Dysprosium - D
- Europium - E
- Galium - G
- Lithium - L
- Magnesium - M
- Ruthenium - R
- Titanium - T
- Xenon - X (The onley element begining with X)
- Zinc - Z
- A used to be argon, but it was changed to Ar (presumably because, since it would usually occur alone, it would look fantastically confusing). D is deuterium and T is tritium. J was once used for iodine, from German Jod (today Iod is used, though you may find this usage from as recently as the 1970s). G used to be for beryllium, which previously was called "glucinium" (for the sweet taste of its salts, which are however fantastically poisonous; the name "beryllium" was suggested instead because some yttrium salts are also sweet). Some of the others are "generic" symbols: E is for any electrophile, L for any ligand, M for any metal, R for any alkyl group (sometimes also for radicals), and X for any halogen (sometimes X, Y, and Z are used when multiple generic elements from the same group are needed, even though Y is also yttrium). That leaves Q, which is easy to explain because no element has it in its name. Double sharp (talk) 04:56, 25 December 2016 (UTC)
- Strictly speaking, generic symbols are not an obstacle for an element symbol. I personally think that in most cases, two-letter symbols are better because they immeditely provide more context. I remember that when Berkeley first synthesized einsteinium, they wanted to use the symbol E. The current symbol Es is better as it does not make you think for another half a second, "what 'E' are we talking about?", since einstenium is a rare (in fact, sythethic) element.
- Hydrogen, oxygen, and other one-letter elements are very common. They don't need that context.
- (Also, just since you mentioned Jod: it is still the norm, at least per actual usage, in German outside chemistry per my knowledge. (After writing this, I checked German Wiki. The article begins with "Iod (standardsprachlich: Jod)," so I must be right.) I can easily tell the same is correct for Russian, which I only learned from Wiki, as I had never encountered the spelling "иод" (iod) in real life. Chemists are keen on regulating spellings, apparently: see WP:ALUM to get an example from English.)--R8R (talk) 10:21, 25 December 2016 (UTC)
- To some extent I think yttrium should have remained as Yt, because we want Y fairly often as the natural follow-up to generic X. You are right that they are not obstacles (we deal with it for yttrium), but these meanings are essentially so standardised that it would be needlessly confusing, so even if they are not forbidden de jure (as far as IUPAC can be considered such) they essentially are de facto.
- Also, thanks for the interesting information about iodine! Most of the German literature I read about it is naturally chemical-oriented and hence uses the spelling with the i. The spelling regulation is useful for sorting and indexing databases, at least: no one wants to search for iodine oxides under both "I" and "J". Double sharp (talk) 10:44, 25 December 2016 (UTC)
I suggest organization of elements into these categories:
- Alkali metals: Li, Na, K, Rb, Cs, Fr
- Alkaline earth metals: Be, Mg, Ca, Sr, Ba, Ra
- Lanthanides: La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb
- Actinides: Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No
- Transition metals:
- Platinum group: Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt
- Noble metals: Ru, Rh, Pd, Ag, Os, Ir, Pt, Au
- Coinage metals: Cu, Ag, Au
- Volatile metals: Zn, Cd, Hg
- Superheavy elements: Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg, Cn
- Other transition metals: Sc, Ti, V, Cr, Mn, Y, Zr, Nb, Mo, Tc, Lu, Hf, Ta, W, Re
- Post-transition metals:
- Icosagens: Al, Ga, In, Tl, Nh
- Crystallogens: Sn, Pb, Fl
- Pnictogens: Bi, Mc
- Chalcogens: Lv
- Superheavy elements: Nh, Fl, Mc, Lv
- Icosagens: B
- Crystallogens: Si, Ge
- Pnictogens: As, Sb
- Chalcogens: Te, Po
- Halogens: At
- Polyatomic nonmetals:
- Crystallogens: C
- Pnictogens: P
- Chalcogens: S, Se
- Diatomic nonmetals:
- Hydrogen: H
- Pnictogens: N
- Chalcogens: O
- Halogens: F, Cl, Br, I
- Superheavy elements: Ts
- Polyatomic nonmetals:
- Noble gases: He, Ne, Ar, Kr, Xe, Rn, Og
- Superheavy elements: Og
- This article is about The periodic table of the elements. If you would like to organize elements into new categories, feel free to write up a proposed organizational scheme for the periodic table, submit it for peer review and publication in a journal with a reasonably high impact score. Once your scheme has been published and accepted by the academic community, bring it back here for inclusion in the article. - SummerPhDv2.0 02:26, 14 February 2017 (UTC)
- If you have reliable sources showing that these subcategories are widely used re the periodic table, please provide those sources.
- If the subcategories are not widely used in re the periodic table, there is nothing to discuss here. - SummerPhDv2.0 02:50, 14 February 2017 (UTC)
This system is OK. Nearly all of the categories are shown on the periodic table in the article, here. The refractory metals and the noble metals are mentioned just below that table, here. Other category names are listed in Names for sets of chemical elements. Sandbh (talk) 06:27, 14 February 2017 (UTC)
- One flaw in your proposal is that you mix up two categorisation schemes. From "Alkali metals, ..." (by metallic characteristics) you flip into "Superheavy elements", (by atomic mass). That is the same as sorting a heap of vegetables by color in the morning and the rest, in afternoon, by size. -DePiep (talk) 13:03, 14 February 2017 (UTC)
You might like to ask WikiProject_Elements about adding extra category names to the info box for each element. For example, gold's Element category ony shows as transition metal, but it is also a coinage metal, a native metal, a noble metal, a platinum group metal, and a precious metal. Sandbh (talk) 23:02, 14 February 2017 (UTC)