ordering

[Madeline Lequang 1G]

Does anybody know a fool proof way of ordering cations and anions according to their polarizability and their polarizing power? My TA said that for cations we can determine it thoughh the atomic radii then the charges, but which one takes precedence? And for anions do we need to focus on the charges or can we just look at their electronegativity?

[Camille Marangi 2E]

I believe atomic radii takes precedence over the ionic charges especially in terms of the row that the atom comes from. The larger in magnitude row on the periodic table, the larger the energy shell and thus nuclear effective charge becomes less effective as we go down the table. So the larger the atom (or anion), the higher its polarizability and the opposite can be said for cations in that the smaller it is (in terms of atomic radius and then ionic charge), the greater its polarizing power.

[Ashley Odibo Dis3E]

So if radii takes presedence over charge then when ordering cations (Li+, Ca2+, Cs+,Ba2+) from least to most polarizing power and anions (I-, Cl-, S2-, P3-) from least to most polarizable, would it be:

Least---------> Most
Cs+, Ba2+,Ca2+,Li+

Cl- S2-,P3-, I -