Question

Why on moving down the group the lower oxidation state of group 13 element becomes more stable?

Answer 1

Answer:

This effect is known as inert pair effect. In case of group 13 elements, the electronic configuration is ns2 np1 and their group valency is +3. However, on moving down the group, the +1 oxidation state becomes more stable. This happens because of the poor shielding of the ns2 electrons by the d- and f- electrons