Which one of the following pairs of atoms/atom-ion have identical ground state configuration?

Options

A. `Li^(+)` and `He^(+)`
B. `Cl^(-)` and `Ar`
C. Na and K
D. `F^(+)` and Ne

Answer

B

Explanation

Both `Cl^(-)` and Ar have identical ground state configuration `(1s^(2)2s^(2)2p^(6)3s^(2)3p^(6))`.