p-Block Elements-I 1 Question 7
7. The increasing order of atomic radii of the following Group 13 elements is
(2016 Adv.)
(a) Al $<$ Ga $<$ In $<$ Tl
(b) $\mathrm{Ga}<\mathrm{Al}<\mathrm{In}<\mathrm{Tl}$
(c) $\mathrm{Al}<$ In $<\mathrm{Ga}<\mathrm{Tl}$
(d) $\mathrm{Al}<\mathrm{Ga}<\mathrm{Tl}<$ In
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Answer:
Correct Answer: 7. (b)
Solution:
- Due to poor shielding of $d$-orbital in $\mathrm{Ga}$, atomic radius of $\mathrm{Ga}$ is smaller than that of $\mathrm{Al}$. Thus, $\mathrm{Ga}<\mathrm{Al}<\mathrm{In}<\mathrm{Tl}$.
