Given below are two statements : Statement (I) : The metallic radius of Al is less than that of Ga. Statement (II) : The ionic radius of $\mathrm{Al}^{3+}$ is less than that of $\mathrm{Ga}^{3+}$. In the light of the above statements, choose the most appropriate answer from the options given below :

(B) Statement I is incorrect but Statement II is correct

(A) Both Statement I and Statement II are incorrect

(C) Statement I is correct but Statement II is incorrect

(D) Both Statement I and Statement II are correct

JEE Main · 2025 · 02 Apr 2025 · Shift 1 · Classification of Elements and Periodicity

Given below are two statements :

Statement (I) : The metallic radius of Al is less than that of Ga.
Statement (II) : The ionic radius of

Al^{3 +}

is less than that of

Ga^{3 +}

.
In the light of the above statements, choose the most appropriate answer from the options given below :

(A)Both Statement I and Statement II are incorrect
(B)Statement I is incorrect but Statement II is correct✓ Correct
(C)Statement I is correct but Statement II is incorrect
(D)Both Statement I and Statement II are correct

Answer: (B)

Solution

Gallium follows aluminium only after the 3d subshell is filled, and those d electrons shield the nucleus poorly, so the greater effective nuclear charge pulls gallium's outer shell inward; its metallic radius is in fact smaller than aluminium's. The claim that aluminium has the smaller metallic radius is therefore wrong. For the tripositive ions the d-contraction is much weaker and the usual increase down the group holds, so

Al X^{3 +}

is smaller than

Ga X^{3 +}

. The first statement is incorrect and the second is correct.

JEE Main · 2025 · 02 Apr 2025 · Shift 1 · Single correct option

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JEE Main · 2025 · 02 Apr 2025 · Shift 1 · Classification of Elements and Periodicity

Solution

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