Question

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

Answer 1

We can define that the oxidation state as the oxidation degree (loss of an electron) in a chemical compound. Most transition metals show multiple oxidation separated by a single electron due to a small increase in successive ionization energies.

Complete step by step answer: From the periodic table, we know the transition metals are elements present in groups 3-12. The transition metals are otherwise known as the d-block elements. These elements are characterized by their partially occupied d subshells in the free elements or in their cations. The variation in the oxidation states of transition elements is due to the incomplete filling of d orbitals in such a way that their oxidation states vary from each other by unity.
We can define the non-transition elements as the main group elements, which are nothing but the s-block and p-block elements. Elements like sodium, potassium, magnesium, strontium, oxygen, sulfur, chlorine and bromine are some of the non-transition elements.

The variable oxidation state of transition elements is due to the participation of (n-1)d orbitals and ns orbitals. The oxidation states of the transition elements differ by unity.
Let us take the example of element vanadium. Vanadium has 4 oxidation states and they are $+ 2, + 3, + 4$ and $+ 5$ oxidation states and manganese has 6 oxidation states and they are $+ 2, + 3, + 4, + 5, + 6$ and $+ 7$ oxidation states.

On the other side, p-block elements show oxidation state varying by two units due to inert part effect. For this case, let us take the example of tin. Tin has $+ 2$ and $+ 4$ oxidation states, indium has ${\text{ + 1}}$ and ${\text{ + 3}}$ oxidation states.

Note:
- In case of transition elements of the same group, higher oxidation state is more stable for heavier elements.
- In case of non-transition elements of p-block, lower oxidation state is more stable because of inert pair effect.