Incorrect order of radius is:

Options

A. `Sr^(2+) lt Rb^(+) lt Br^(-) lt Se^(2-)`
B. `Nb^(5+) lt Zr^(4+) lt Y^(3+)`
C. `Co gt Co^(2+) gt Co^(3+) gt Co^(4+)`
D. `Ba^(2+) lt Cs^(+) lt Se^(2-) lt As^(3-)`

Answer

D

Explanation

`Se^(2-)` and `As^(3-)` related with 4th period, while `Ba^(2+) and Cs^(+)` related with 6th period. (these are not isolectronic species).