Question

Given below are two statements: One is labelled as
Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Both $O^{2-}$ and $M{g}^{2+}$ isoelectronic species.
It the light of the above statements, choose the correct answer from the options given blow.

Answer 1

Correct order of ionic radii:
$O^{2-}>M{g}^{2+}$
This is because among isoelectronic species, the sizes of anions are greater than the sizes of cations. This happens so due to greater interelectronic repulsion in anions.
Statement (II) is correct as both $O^{2-}$ and $M{g}^{2+}$ are isoelectronic.