**COVALENT CHARACTER INCREASES WITH INCREASING CHARGE EITHER ON CATION OR ON ANION-WHY?

Covalent character is in accordance with fajans rules. the covalent character is more either when polarizing power of cation is more or polarizabilty of anion is more. Because in both these cases the distorsion of electron cloud will be more, thus imparting more covalent character.
the covalent character is more , when polarizing power of cation is more when its charge density is more, i.e. its charge is more.
similarly, the covalent character is more, when polarizabilty of anion is more.i.e. its size is more (which happens when its charge is more).

I hope this is clear to you.