Question

why is variability of oxidation states of transition metals diff. frm that of the non transition metals

Answer 1

Non transition elements like alkali metal and alkaline earth metal possess, either 1 or 2 valence electron. These electrons are in their ns orbitals. Whereas the transition elements have large number of valence electron in both s (2) and d (10) orbital. That is why they show variable oxidation state.