Question

The stability of +1 oxidation state among $Al,Ga,In$ and $TI$ increases in the sequence :

• A. $TI<In<Ga<Al$
• B. $In<TI<Ga<Al$
• C. $Ga<In<Al<TI$
• D. $Al<Ga<In<TI$

Answer 1

The correct option is D $Al<Ga<In<TI$

Due to inert pair effect, the s orbital electrons will not be able to overlap effectively, thereby making +1 the more stable oxidation states as we go down the group.

$\therefore$ The stability order of the +1 ion is $T{I}^{+}>I{n}^{+}>G{a}^{+}>A{l}^{+}$