Question

The correct increasing order of the stability of $Al ^{+}, Ga ^{+}$ $ln ^{+}, Tl ^{+}$ ions are:

• A. $Al ^{+}< Ga ^{+}< Tl ^{+}< In ^{+}$
• B. $Al ^{+}< Ga ^{+}< In ^{+}< Tl ^{+}$
• C. $Tl ^{+}< In ^{+}< Ga ^{+}< Al ^{+}$
• D. $Tl ^{+}< Al ^{+}< Ga ^{+}< In ^{+}$

Answer 1

Answer: (B)

Group $13 $ elements have three electrons in their outermost shell with the valance electronic configuration, $ns ^{2} np ^{1}$

Oxidation states of the boron family is $+3$ or $ +1$

Due to inert pair effect, on moving down the group stability of higher oxidation state decrease. Thus; the stability of $+1 $ state increases.