Cation size and covalent character

[Kelly Yun 2I]

Hi, can someone explain the relationship between cation size and covalent character (solubility)? I only remember taking notes on the changes of halide anions affecting solubility.

[Yuelai Feng 3E]

Hi! Cations with higher polarizing power (which are smaller & with higher charge density) tend to form bonds with more covalent characters. This is because the cation exerts higher electrostatic attraction on the electrons surrounding the anion, causing them to delocalize and form something similar to a shared e- pair in a covalent bond. Usually, the more covalent character a chemical has, the less soluble it is. Hope it helps!

[Kelly Yun 2I]

Oh, I see so size of cations and polarizing power and size of anions and polarizability are the opposite right? Thanks!

[Brennan McGurrr 3C]

Yes they are opposite. Polarizing power measures a cation's ability to distort electron clouds, while polarizability measures an anion's ability to have its electron clouds distorted.

[Kelly Ha 1K]

Oh, I see so size of cations and polarizing power and size of anions and polarizability are the opposite right? Thanks!

Yes, larger anions have greater polarizability and smaller cations have greater polarizing power.

[Kelly Yun 2I]

Oh, I see so size of cations and polarizing power and size of anions and polarizability are the opposite right? Thanks!

Yes, larger anions have greater polarizability and smaller cations have greater polarizing power.

Okay, thank you so much :) Happy Thanksgiving!