Chemistry - PERIODIC TABLE Question with Solution | TestHub

For isoelectronic species, as nuclear charge increases radius decreases. Greater the positive charge, the lesser the size of the ion. Greater the negative charge, the larger the size of an ion.

$$\begin{gathered} {\mathrm{Ca}}^{2+}< {\mathrm{K}}^{+} < {\mathrm{Cl}}^{-} < {\mathrm{S}}^{2-} \\ \mathrm{p} 20 19 17 16 \\ \mathrm{e} 18 18 18 18 \end{gathered}$$

So, the correct option is (D).