Which of the following species has unpaired electrons?

Options

A. `O_(2)^(2-)`
B. `F_(2)`
C. `N_(2)`
D. `O_(2)^(Θ)`

Explanation

(i) `O_(2)^(2-) (8+8+2 =8e^(-')s)` number of remaining `e^(-')s`
`= 18 -8 =10 e^(-)`
`N_(b) = 6, N_(a) =4` [All `e^(-')s` in bonding and anti bonding `MO` are paired
(ii) `F_(2) 7+7 =14e^(-'s)` number of remaining `e^(-')s`
` = 18 -8 =10 e^(-')s`
`N_(b) = 6,N_(a) =4` [All `e^(-')s` are paired]
(iii) `N_(2) (7 +7 =14 e^(-')s)` number of remaining `e^(-')s`
`= 14 - 8 = 6 e^(-')s`
`N_(b) =6, N_(a) =3` [All `e^(-')s` in bonding `MO` are paired]
(iv) `O_(2)^(Θ)(8 + 8 + 1 =17 e^(-')s)` number of remaining `e^(-')s`
`=17 - 8 = 9 e^(-')s`
`N_(b) =6,N_(a) =3` [Antibonding `MO` has one unpaired `e^(-')`] Thus `O_(2)^(Θ)` is the only species having unpaired `e^(-)` .