Question

Which of the following has largest radius?

• A. $O^{2-}$
• B. $M{g}^{2+}$
• C. $N{a}^{+}$
• D. $F^{-}$

Answer 1

The correct option is A $O^{2-}$

The given ions are isoelectronic species. In case of isoelectronic species, more is the negative charge on the ion, lesser is the effective nuclear charge, more will be the radius. So, $O^{2-}$ has largest radius among the following.