Question

what factors cause the cation to be strongly hyderated ?

Answer 1

its charge to size ratio

Answer 2

IT'S POLARISING ABILITY.
'S SMALLER THE CATION, MORE WILL BE IT'S POLARISING ABILITY.
AND HIGHER THE CHARGE ON THE CATION MORE WILL BE IT'S POLARISING ABILITY.,
SEE FAJAN'S RULES ..!!
THESE RULES DICTATES THIS HYDRATION BY CATIONS!!

Answer 3

a compound's ability to form a dative covalent bond with water is what controls whether it's hydrated or not, so first it must be the cation of a metal with a high polarization ability, and free subshells for bonding to happen, thats why some transition metals form strongly hydrated compounds as they usually have the d subshell to fill