Question

Arrange the following as stated :
Increasing order of ionic size
$N^{3-},N{a}^{+},F^{-},O^{2-},M{g}^{2+}$

• A. $M{g}^{2+}<Na<F^{-}<O^{2-}<N^{3-}$.
• B. $Na<M{g}^{2+}<F^{-}<O^{2-}<N^{3-}$.
• C. $O^{2-}<Na<F^{-}<M{g}^{2+}<N^{3-}$.
• D. None of these

Answer 1

The correct option is A $M{g}^{2+}<Na<F^{-}<O^{2-}<N^{3-}$.

The increasing order of ionic sizes is
$M{g}^{2+}<Na<F^{-}<O^{2-}<N^{3-}$.
All of these are isoelectronic ions.
In isoelectonic species, as the number of protons (atomic number) goes on increasing, size goes on decreasing due to stronger attraction on the electrons.