JEE Main · 2022 · 26 Jun 2022 · Shift 1 · p-Block Elements

Choose the correct stability order of group 13 elements in their +1 oxidation state.

(A) $Al < Ga < In < Tl$ ✓ Correct
(B) $Tl < In < Ga < Al$
(C) $Al < Ga < Tl < In$
(D) $Al < Tl < Ga < In$

Answer: (A)

Solution

In group 13, the stability of the +1 oxidation state increases down the group due to the inert pair effect. The 6s² electrons in heavier elements become increasingly reluctant to participate in bonding. Therefore, Tl⁺ is most stable, while Al⁺ is least stable.

Stability order:

Al < Ga < In < Tl

JEE Main · 2022 · 26 Jun 2022 · Shift 1 · Single correct option

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