Question

Thallium shows different oxidation states because:

• A. of its high reactivity
• B. of inert pair effect
• C. of its amphoteric nature
• D. it is a transition metal

Answer 1

The correct option is B

of inert pair effect

This is due to inert pair effect. It is defined as the inability of the $n{s}^2$ electrons present in the valency shell to take part in the process of bonding. Thallium belonging to group III A shows a general valency electronic configuration of $n{s}^{2}n{p}^1$ and therefore exhibits less stable +3 and more stable +1 oxidation state due to inert pair effect.