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Posted: Sun Nov 17, 2019 1:10 pm
What's the concept behind the polarizability of anions/cations?
Posted: Sun Nov 17, 2019 1:14 pm
Typically, cations will have less polarizability because there are less electrons and therefore the effective nuclear charge on the electrons are stronger and pulled in closer to the nucleus. Therefore, it is harder to "distort" the electron cloud making it less polarizable. The opposite is said for anions.
Posted: Sun Nov 17, 2019 1:17 pm
Polarizability in anions is how easily the electron cloud of an atom is distorted. It's a greater value for larger anions.
For cations, polarizability is low but polarizing power is high (how easily it can attract the electrons from another atom. This value is typically greater for smaller, more positively charged cations).
These values are related to how easily certain atoms can form dipole moments.
Posted: Sun Nov 17, 2019 8:18 pm
Polarizability increases with size and negative charge. So larger anions have the highest polarizability.
Posted: Sun Nov 17, 2019 9:00 pm
Polarizability is a concept of size with anions and cations. Since anions are larger than their respective neutral states because of having more electrons, it is easier to distort (move the electrons around the atom) the electron cloud. With respect to cations, they have polarizing strength, meaning that they can penetrate these polarizable anions and shift the electrons around the atom. This is important in determining ionic and covalent character, bond strength, dipole moments, intermolecular forces, and strength of acids and bases.