Browse Questions

# Among the following,the paramagnetic species is

$\begin{array}{1 1}(a)\;F_2&(b)\;C_2\\(c)\;O_2&(d)\;CO\end{array}$

$F_2(18):(\sigma 1s)^2 < (\sigma^*1s)^2 < (\sigma 2s)^2 < (\sigma^*2s)^2 < (\sigma 2p_x^2 < (\pi 2p_x^2=\pi 2p_y^2) < (\pi^*2p_x^2=\pi 2p_y^2)$
$C_2(12):(\sigma 1s)^2 < (\sigma^*1s)^2 < (\sigma 2s)^2 < (\sigma^* 2s)^2 < \pi 2p_x^2=\pi 2p_y^2)$
$O_2(16):(\sigma 1s)^2 < (\sigma^*1s)^2 < (\sigma 2s)^2 < (\sigma^*2s)^2 < (\sigma 2p_x^2 < (\pi 2p_x^2=\pi 2p_y^2) < (\pi^*2p_x^1=\pi 2p_y^1)$
$CO(14):(\sigma 1s)^2 < (\sigma^*1s)^2 < (\sigma 2s)^2 < (\sigma^*2s)^2 < (\sigma 2p_x^2 < (\pi 2p_x^2=\pi 2p_y^2)$
In all these species in only $O_2$ unpaired electrons are there.$O_2$ is paramagnetic.
Hence (c) is the correct answer.