The radius of which ion is closed to that of the Li+ ion?
(A) Na+
(B) Be2+
(C) Mg2+
(D) Al 3+
I chose (B) but the answer is (C)
My reasoning is that Mg2+ Zeff charge is strong enough to pull all its electrons to match Li+'s. But how do you know that Mg2+ nuclear charge is similar to Li+ than Be2+? In Be2+, you only remove 2 electrons so shouldn't it be close to Li+?