Question

The correct order of ionic size of the species $K^{+},C{l}^{-},C{a}^{2+}$ and $S^{2-}$ is:

• A. > > > .
• B. > > > .
• C. > > > .
• D. > > > .

Answer 1

The correct option is A

> > > .

Ionic size depends upon the charge on the ion. Higher the negative charge, greater will be the size of an anion provided all of them have same number of electrons

All the four ions have 18 electrons in total. Higher the positive charge, smaller will the size of a cation. So, the correct order is
$S^{2-}$ > $C{l}^{-}$ > $K^{+}$ > $C{a}^{2+}$.