Which of the following is correct?

Options

A. radius of `Ca^(2+) lt Cl^(-) lt S^(2-)`
B. radius of `Cl^(-) lt S^(2-) lt Ca^(2+)`
C. radius of `S^(2-)=Cl^(-)=Ca^(2+)`
D. radius of `S^(2-) lt Cl^(-) lt Ca^(2+)`

Answer

A

Explanation

Number of electrons in `Ca^(2+),S^(2-) and Cl^(-)=16`. i.e., all three ions are isoelectronic. For any ion, ionic radius `prop(e//Z)` [where, e=electron number and Z=atomic number]. Therefore the correct order of the radii of the gviven three ions are `--Ca^(2+) lt Cl^(-) lt S^(2-)`.