How is the variability in oxidation states of transition metals different from that of the non transition metals?
Illustrate with examples.

Answer

The Variability in oxidation state of transition matals is due to the incomplete filling of d-orbitals in such a way that their oxidation state differ from each other by unity e.g.,`Fe^(2+)` and `Fe^(2+)` and `Fe^(3+)` , Cu^(+) and `Cu^(2+)` etc. In case of non-transition elements. the oxidation states differ by units of two e.g., `Pb^(2+)` and `Pb^(4+)` , `Sn^(2+)` and `Sn^(4+)` etc. Moreover, in transition elements , the higher oxidation state are more stable for heavier elements in a group. In p-block elements , the lower oxidation state are more stable for heavier members due to inert pair effect, e.g in group- `16`,`Pb`(II) is more stable than `Pb(Pb)`.