Question

Arrange the following species in the increasing order of their ionic radii giving reasons. ${\mathrm{Mg}}^{2+},{\mathrm{Al}}^{3+},{\mathrm{O}}^{2-},{\mathrm{Na}}^{+},{\mathrm{N}}^{3-},{\mathrm{F}}^{-}$.

Answer 1

Ionic radii:

• The ion listed above include $10$ electrons. So, all the species are isoelectronic.
• The radius of an anion is always greater than the radius of the cation.
• The higher the charge on an anion, the greater the ionic radii.
• The higher the charger on the cation, the lesser the ionic radii.

Increasing order of ionic radii:

• So, the ionic radii in the increasing order are as follows:-

${\mathrm{Al}}^{3+}<{\mathrm{Mg}}^{2+}<{\mathrm{Na}}^{+}<{\mathrm{F}}^{-}<{\mathrm{O}}^{2-}<{\mathrm{N}}^{3-}$