Which one of the following is the smallest in size?

Options

A. `F^(-)`
B. `O^(2-)`
C. `N^(3-)`
D. `Na^(+)`

Answer

D

Explanation

They are all isolectronic species for which size is inversely related to atmoic number. Thus, the correct order of size is
`N^(3-)(Z = 7) gt O^(2-) (Z = 8) gt F^(-) (Z = 9) gt Na^(+) (Z = 11)`