Polarizability

[Kyle Harvey 4F]

How does polarizability relate or depend on the number of electrons and the size of the atom or molecule?

[Jessica Booth 2F]

The bigger the atom, the more polarizable it will be because the outer electrons feel the pull of the nucleus less so they can be more distorted. The number of electrons is indicative of the size.

[Naji Sarsam 1F]

It is important to distinguish between polarizing power and polarizability. Polarizing power is the ability of an atom to polarize another. Polarizability is the opposite: the ability of an atom to be polarized.

Polarizability is similar to the trend of electronegativity. An atom is more polarizable for the following reasons:
1.) if it has more electrons, meaning there is more inner electron shielding
2.) if the atom is bigger so that the further electrons are more weakly bound
Thus polarizability increases going down a group and going left a period. Making Francium the most polarizable atom. This parallels the trend of electronegativity but in the opposite direction. Thus a short cut to determining the polarizability of an atom is that the most polarizable atoms have the least electronegativity.

[Omar Selim 1D]

For anions, polarizability increases the more electrons it has. For cations, it depends on how small and how charged the ions are