Question

Thallium shows different oxidation states because -

• A. It is a transition metal
• B. Of inert pair effect
• C. Of its amphoteric character
• D. Of its high reactivity

Answer 1

The correct option is B

Of inert pair effect

Inert pair effect is the phenomenon in which outer shell (ns2)electrons penetrate to
(n - 1) d electrons and thus becomes closer to nucleus and are more effectively pulled towards nucleus. This results in less availability of ns electrons for bonding. The inert pair effects begins when n = 4 and increases with increasing value of n.