The correct decreasing order of ionic size among the following species is `K^+, Cl^-, S^-2` and `Ca^(+2)`.

Options

A. `Ca^(2+) gt Cl^(-) gt S^(2-) gt P^(3-)`
B. `S^(2-) gt P^(3-) gt Cl^(-) gt Ca^(2+)`
C. `P^(3-) gt S^(2-) gt Cl^(-) gt Ca^(2+)`
D. `Ca^(2+) gt Cl^(-) gt S^(2-) gt P^(3-)`

Answer

D

Explanation

`._(15)P^(3-),._(16)S^(2-),._(17)Cl^(-)` belong to 3rd period wheras `._(20)Ca^(2+)` belong to 4th period. These are isoelectronic ions and therefore size depends on nuclear charge. More is nuclear charge smaller is size