Question:
The correct order of ionic radii for the ions, $\mathrm{P}^{3-}, \mathrm{S}^{2-}$, $\mathrm{Ca}^{2+}, \mathrm{K}^{+}, \mathrm{Cl}^{-}$is :
Correct Option: 1
Solution:
$\mathrm{P}^{3-}>\mathrm{S}^{2-}>\mathrm{Cl}^{-}>\mathrm{K}^{+}>\mathrm{Ca}^{2+}$
(Correct order of ionic radii)
all the given species are isoelectronic species. In isoelectronic species size increases with increase of negative charge and size decreases with increase in positive charge.