Question:
The correct order of the ionic radii of $\mathrm{O}^{2-}, \mathrm{N}^{3-}, \mathrm{F}^{-}, \mathrm{Mg}^{2+}$, $\mathrm{Na}^{+}$and $\mathrm{Al}^{3+}$ is :
Correct Option: , 3
Solution:
All are isoelectronic species, so more is the $Z_{\text {eff }}$ less will be the ionic size.
$\therefore$ Correct order of ionic radii is
$\mathrm{Al}^{3+}<\mathrm{Mg}^{2+}<\mathrm{Na}^{+}<\mathrm{F}^{-}<\mathrm{O}^{2-}<\mathrm{N}^{3-}$