Least to Most Polarizable/Polarizing Power

[Hai-Lin Yeh 1J]

Order these anions in order from least to most polarizable: Br-, S2-, O2-, P3-

Order these cations in order from least to most polarizing power: Li+, Mg2+, Na+, Be2+

[Ester Garcia 1F]

O2- < S2- < P3- < Br-

Na+ < Mg2+ < Li+ < Be2+

feel free to @ me if I'm wrong

[Hai-Lin Yeh 1J]

Why is S2- < P3-? and why is Mg2+ < Li+?

[405112316]

Both size and charge need to be taken into account when organizing atoms. The charge density, which is a measure of the charge in terms of the volume that the atom takes up, is used to compare atoms to each other (not solely charge or solely size). s2- is smaller and should be more difficult to polarize (higher polarizing power though) because its atoms are held closer to it. Mg2+ should have more polarizability because it is bigger than Li2+.