Details of Answers about All Periodic Tables
What other locations for elements are in question?
Placement of exit/re-entry points of the Rare earths are also in dispute, some (including the IUPAC) leaving a blank on the flat chart below Sc & Y, others putting La & Ac there, and some promoting Lu & Lr for that spot.
Details of answer;
Subdivisions of the PT include naming some as 'blocks', relative to similarities, although there is evidence that there are cases of wrong physics (and wrong arithmetic) in the inclusion of some elements in one or the other block. NoneTheless, they are commonly identified as follows;
s-elements: elements for which the outer or valency electron shell is an unfilled s-shell.
p-elements: elements with an unfilled p-shell as valency electron shell.
The s-elements and p-elements together form the main group elements (IA to VIIIA).
d-elements: elements with an unfilled d-shell as valency electron shell.
these form the transition elements (groups IB to VIIIB).
f-elements: elements with an unfilled f-shell as valency electron shell.
these form the inner transition elements (lanthanoids and actinoids). Although they are classed as 4f and 5f elements, it should be noted that the electronic configuration of :
• La is 6s25d1 instead of 6s24f1;
• Ac is 7s26d1 instead of 7s25f1;
• Lu is 6s24f145d1; and
• Lr is 7s25f146d1.
A Wikipedia author also examines the issue;
Lutetium is a d-block lanthanide. Whether it’s a group 3 element depends on which periodic table one uses. I agree that we need coordination and consistency, but I would not assert so strongly that La and Ac are in group 3. That is ambiguous also.
Some tables include lanthanum (La) and actinium (Ac), (The beginnings of the lanthanide and actinide series of elements, respectively) as the remaining members of group 3. In their most commonly encountered tripositive ion forms, these elements do not possess any partially filled f orbitals, thus resulting in more d-block-like behavior.
Some tables include lutetium (Lu) and lawrencium (Lr) as the remaining members of group 3. These elements terminate the lanthanide and actinide series, respectively. Since the f-shell is nominally full in the ground state electron configuration for both of these metals, they behave most like d-block metals out of all the lanthanides and actinides, and thus exhibit the most similarities in properties with Sc and Y. For Lr, this behavior is expected, but it has not been observed because sufficient quantities are not available.
Some tables refer to all lanthanides and actinides by a marker in group 3. A third and fourth alternative are suggested by this arrangement:
the third alternative is to regard all 30 lanthanide and actinide elements as included in Group 3. Lanthanides, as electropositive trivalent metals, all have a closely related chemistry, and all show many similarities to Sc and Y.