How can we show that change in oxidation state is different from variable oxidation state for non transition element ?

Explanation

The variability of oxidation states, a characteristic of transition elements, arises out of incomplete filling of d-orbitals in such a way that their oxidation states differ from each other by unity e.g.. `V^(II) V^(III) V^(IV)V^(V)` This is in contrast with the variability of oxidation state where oxidation states normally differ by a unit of two