Given below are two statements: Statement I: The metallic radius of Al is less than that of Ga. Statement II: The ionic…

🧠 d-block contraction shrinks neutral Ga below Al, but ionic radii flip In the neutral atoms, Ga is smaller than Al because of $3d$-electron shielding being poor. But in the $3+$ ionic state, the $3d^{10}$ electrons in $\ce{Ga^{3+}}$ add a full extra inner shell — so the ionic radius of $\ce{Ga^{3+}}$ is larger than $\ce{Al^{3+}}$.

🗺️ Evaluate the two statements Statement I: "Metallic radius of Al is less than Ga." Metallic radius: $\ce{Al} = 143$ pm, $\ce{Ga} = 135$ pm. Al is larger than Ga. Statement I is false. Statement II: "Ionic radius of $\ce{Al^{3+}}$ is less than $\ce{Ga^{3+}}$." Values: $\ce{Al^{3+}} = 53.5$ pm, $\ce{Ga^{3+}} = 62$ pm. Statement II is true.

$\boxed{\text{Answer: (b)}}$