Ho aspirant,

The ability of a cation to distort an anion by changing its shape and size is known as its polarization power and the tendency of the anion to get polarized by the cation is known as its polarizability. In other words, it is the ability of cation to attract valence electron shell from nearby anion.

We have Fajan's rule for calculating Polarizing extent. It depends on following points:

• Small size of cation:
  Smaller size of cation greater is its polarizing power
• Large size of anion: larger the size of anion, greater is Polarizing power
• Large charge on either of the two ions
• Electronic configuration: for the ions with same size and charge, one with pseudo noble gas(18 electrons in outermost shell) configuration is more Polarizing than ions with noble gas configuration ( 8 electrons in outermost shell).

Accordingly you can get order.

Hope this helps.