Wikipedia:WikiProject Elements/PTG/background

The PT in other wikis

 * en, de wiki show viewcounts; enwiki: 23k/day; dewiki: 5200/day

Off-wiki examples

 * primefan.ru 2018 (has Z sub-prefixed ;-) (Droog Andrey at WT:ELEM ~yesterday; Ds is enthousiastic) 28 February 2018)
 * PubChem

About asterisks
This edit by Double sharp I'd like to keep :-) -DePiep (talk) 11:49, 24 January 2021 (UTC) "Regarding the asterisks

Of interest might be the earlier 1988 report on this matter. Although this is where the compromise apparently came from, it then spends a funnily large amount of time detailing how Sc-Y-Lu-Lr works, and the subsequent 1990 IUPAC Red Book appeared inconsistently with a Sc-Y-*-** 18-column table and a Sc-Y-Lu-Lr 32-column table.

“ 	According to the electron configurations of the elements, the scandium

group consists of the elements Sc, Y, Lu, Lr.

This was pointed out as early as 1959 by L.D. Landau (ref. 20) and later by other authors (ref. 13, 14, 20 to 25). Most periodic tables in textbooks and classrooms, however, list Sc, Y, La, and Ac as elements of the scandium group and designate the elements Ce to Lu and Th to Lr as lanthanides and actinides, respectively. The historical background for this arrangement is given in a paper by W.B. Jensen (ref. 21). Based upon their electronic configurations and their chemical and physical properties, the elements La to Yb and Ac to No should be inserted between barium and lutetium and between radium and lawrencium or for practical reasons be listed at the bottom of the table. The series La to Yb and Ac to No then, however, cannot be named correctly as lanthanides and actinides since they contain the elements lanthanum and actinium and not only elements similar to lanthanum and actinium as is purported by the ending -ide (or -oid according to an earlier IUPAC recommendation). ”

Therefore I would say that having asterisks to show where exactly La–Yb and Ac–No belong (between groups 2 and 3), although not explicitly recommended, is surely within the spirit of what is stated given the pains that were taken to explain where exactly they should be inserted. Double sharp (talk) 05:11, 24 January 2021 (UTC)"

- Double sharp


 * Also the report clearly explains that the "long form" refers to the 18-column, pre-actinides (pre-Seaborg) form. As opposed to the "short form", the Mendeleevian 8-gruppe (10-column) PT, with or without the noble gases column (#11). The "32-column" form is not a structural change, it is a graphical notation (alternative to the 18-column plus ~f-block below. Not the depiction (18 or 32 columns), but the addition of the f-block  does require naming like 'Extended long form'. -DePiep (talk) 12:08, 24 January 2021 (UTC)

Basic colors



 * }

Rare earths discoveries

 * Interesting graph


 * Ytterby and Cerium graph -DePiep (talk) 13:08, 26 January 2021 (UTC)