====== Periodic Table standardisation ======

''//Note:// This article is currently in the //Proposed Content// section.''

The //International Union of Pure and Applied Chemistry //(IUPAC) publishes the one of  the recognised [[https://iupac.org/what-we-do/periodic-table-of-elements/|global standards]]  for the table of chemical elements.

But the layout of the// Periodic Table//, which groups chemical elements according to their electronic properties (i.e. free electrons), has //not// been universally agreed upon.

There are continuing disagreements about 'Group 3' (which, according to IUPAC, currently contains Scandium, Yttrium, Lanthanoids and Actinoids)

>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?

In March 2021, IUPAC published a [[https://iupac.org/wp-content/uploads/2021/04/ChemInt_Jan2021_PP.pdf|discussion document]] on the subject. For the time being, the official version is from 2018 - and some chemists refer to it as a 'compromise'.

''//Editor's note:// This article seems more focused on lack of agreement about classification than 'unknowns' as such.''