Which molecule/ion out of the following does not contain unpaired electrons?

Options

A. `N_(2)^(+)`
B. `O_(2)`
C. `O_(2)^(2-)`
D. `B_(2)`

Answer

C

Explanation

M.O. energy level diagrams of the different species are :
`N_(2)^(+)KK[sigma_(2s)]^(2)[sigma_(2s)^(**)]^(2)[pi_(2px)]^(2)[pi_(2py)]^(2)[sigma_(2pz)]^(1)`
`O_(2):KK[sigma_(2s)]^(2)[sigma_(2s)^(**)]^(2)[sigma_(2pz)]^(2)[pi_(2px)]^(1)`
`[pi_(2py)]^(2)[pi_(2px)^(**)]^(1)[pi_(2y)^(**)]^(1)`
`O_(2)^(2-):KK[sigma_(2s)]^(2)[sigma_(2s)^(**)]^(2)[sigma_(2pz)]^(2)[pi_(2x)]^(2)`
`[pi_(2py)][pi_(2px)^(**)]^(2)[pi_(2py)^(**)]^(2)`
`B_(2):KK[sigma_(2s)]^(2)[sigma_(2s)^(**)]^(2)[pi_(2px)]^(1)[pi_(2py)]^(1)`
`O_(2)^(2-)` ion has no unpaired electrons.