2D.11

[Hannah Kortum 1F]

Could someone please explain why N^3- is more polarizable than O^2- for question 2.D.11?

[Amanda Wong 3D]

N^-3 is more polarizable than O^-2 because both of these ions have the same amount of electrons (8), but different amount of protons. N^-3 has an effective nuclear charge of 5, while O^-2 has one of 6. Because O has a greater nuclear charge, it has a greater attraction to the electrons in the atom-- the electrons are held more tightly. This results in N having a bigger radius, thus being more polarizable, because its electrons are held less tightly.

[Amal Aboumerhi 3E]

Hi, the way that I approached this problem was first by identifying N^3- and O^2- as anions. Anions polarizability increases as the ion gets larger and less electronegative. N^3- is larger in atomic radius than O^2-, which means it is more polarizable.