The paramagnetic behaviour of $B_{2}$ is due to the presence of\

Question

Professor PC Thomas Classes · Answer

(a) : $\mathrm{B}_{2}($ no. of electrons $=10)$ 
The molecular orbital configuration of $B_{2}$ is :\ $\sigma(1 s)^{2} \sigma^{*}(1 s)^{2} \sigma(2 s)^{2} \sigma^{*}(2 s)^{2} \pi\left(2 p_{x}ight)^{1}=\pi\left(2 p_{y}ight)^{1}$\ Thus, paramagnetic behaviour of $B_{2}$ is due to the presence of two unpaired electrons in $\pi$-bonding molecular orbital.\