Talk:Periodic table (detailed cells)

Assessment comment
Substituted at 01:14, 22 May 2016 (UTC)

External links modified
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 * Added archive https://web.archive.org/web/20080213082719/http://www.iupac.org/didac/Didac%20Eng/Didac01/Content/S01.htm to http://www.iupac.org/didac/Didac%20Eng/Didac01/Content/S01.htm
 * Added archive https://web.archive.org/web/20050405073517/http://www.iupac.org/reports/periodic_table/ to http://www.iupac.org/reports/periodic_table/

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IUPAC Guidelines
According to IUPAC guidelines, Lanthanum (La) and Actinium (Ac) must be placed along with f-block elements. Someone please check this and update the table. Hermit  Curator  09:30, 5 June 2018 (UTC)
 * The link is not named "Guideline" but "What we do" (=IUPAC), which is slightly less defining. WRT the periodic table form & content, there are two main considerations involved. One is editorial, the other scientific.
 * scientific: this is about the scientific statements the periodic table makes. For example, it shows helium and neon in the same column 18, so the statement is they are both noble gases and have the same periodic properties. Another statement being made is: "Which elements are in group 3?". The IUPAC page has all lanthanides and actinides in the column labeled "3", plus scandium and ytterbium (the fact that they are graphically moved to the bottom and represented by a placeholder in the main table is irrelevant for this scientific statement). That is 15+15+2=32 elements in group 3.
 * However, unfortunately, the same IUPAC page says: "Group 3: The question of precisely which elements should be placed in group 3 has been debated from time to time. An IUPAC project has been recently initiated to resolve the question. Will group 3 consist of Sc, Y, Lu, and Lr or, will it consist of Sc, Y, La and Ac?". Whatever the result, the outcome is four elements in group 3. This wiki (the English wikipedia) has chosen to primarily present the Sc/Y/La/Ac quartet as being in group 3. That is why most of our PT articles show this group 3 in a periodic table (see Periodic table, and so this template). (Other group 3 variants are mentioned in dedicated articles, for example in Group 3 element). The discussions were at WT:ELEMENTS, now archived here and here.


 * Editorial: As the What-we-do page says in the bottom paragraph: "... IUPAC has no recommendation for a specific form of the periodic table, i.e. 18-column or 32-column format". (The number 18 or 32 is the number of columns that contain elements; the shown form has 18 such columns). Whether there are elements graphically moved to the bottom is an editorial choice only, as both forms represent the same scientific statements (Article Periodic table (large cells) shows both, nicely). And for clarity, given the group 3 composition we want to show, it is more convenient & clear to move only 14+14 elements to the bottom (15+15 would make group 3 needlessly complicated to show, graphically). That is what this template currently shows, and why we want to keep it that way.


 * Conclusion: For these reasons, the requested change should not be made. will be reverted.


 * TL;DR: scientifically, enwiki wants to show that group 3 is Sc/Y/La/Ac. Alle 32 elements in group 3 is not an option any more. A further IUPAC publication wrt this is awaited. Editorially (graphically), in an 18-column periodic table enwiki prefers to keep the four elements in group 3 together in the main table, so not move them to below, because that is graphically the easiest and clearest solution. In 32-column format, the issue does not appear, but care has been taken to keep the scientific presentation the same. Therefor, the requested change should not be made. - DePiep (talk) 11:30, 5 June 2018 (UTC)