Question

Why in d block , higher elemants have more oxidation state?

Answer 1

An oxidation state shows how many electrons an atom would gain or lose if it were to bond with other atoms. Transition metals can have multiple oxidation states because of their electrons.

So, higher oxidation state cations [e.g. Cr(VI) or mn(VII)] are stabilized by the higher solvation (hydration) energy. ... So, the factors that influence very high oxidation state in transition metal compounds are: relative ease of losing valence d-shell electrons without compromising the energetics

Answer 2

In group of d-block elements the oxidation state for heavier elements is more stable as the core (after removing valence electrons the remainder is called core) of these elements is unstable and hence can lose one or more electrons from the unstable core gives higher oxidation states, due to which their covalent character increases and also increases stability.

So, higher oxidation state cations [e.g. Cr(VI) or mn(VII)] are stabilized by the higher solvation (hydration) energy. ... So, the factors that influence very high oxidation state in transition metal compounds are: relative ease of losing valence d-shell electrons without compromising the energetics.