Question

Which of the following species has unpaired electrons?

• A. $N_{2}$
• B. $F_{2}$
• C. $O_{2}^{-}$
• D. $O_{2}^{2 -}$

Answer 1

Answer: (C)

$O_{2}^{-}$

Answer 2

: $O_{2}^{-}:(\sigma 1s^{2})(\sigma*1s^{2})(\sigma 2s^{2})(\sigma*2s^{2})(\sigma 2p_{x}^{2})$

$(\pi 2p_{x}^{2} = \pi 2p_{y}^{2})(\pi*2p_{x}^{2} = \pi*2p_{y}^{1})$

$N_{2},F_{2}$and $O_{2}^{2 -}$have paired electrons.