Question

Stability order of group IIIA (boron family) element is:

• A. $G{a}^{+}<I{n}^{+}<T{l}^{+}$
• B. $G{a}^{3+}>G{a}^{+}$
• C. both $\left(A\right)$ and $\left(B\right)$
• D. none of the above

Answer 1

Answer: (C)

both $\left(A\right)$ and $\left(B\right)$

Inert pair effect may be defined as inertness of the ns sub-shell towards chemical reaction. It is seen in groups 3A and 4A especially (5s and 6s electrons). Therefore, Pb shows mainly $+2$ oxidation state frequently, as compared to $+4$ oxidation state.

So, as we move down the group, due to the inert pair effect, the lower oxidation state becomes more stable.

So,

$G{e}^{2+}<S{n}^{2+}<P{b}^{2+}$

Similarly,

$G{a}^{+}<I{n}^{+}<T{l}^{+}$

$G{a}^{3+}>G{a}^{+}$