Which one of the following ions will be smalllest in size?

Options

A. `Na^(+)`
B. `Mg^(2+)`
C. `F^(-)`
D. `O_(2)^(-)`

Answer

B

Explanation

`Na^(+), Mg^(2+) , O^(2-) and F^(-)` all are isoelectronic but `Mg^(2+)` have 12 protons in his nucleus, so the attraction force on last shell is maximum and hence, it have smallest size