Question

Which of the following is paramagnetic?

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

To determine the magnetic nature of molecules, first we have to draw MO energy level diagrams of all the molecules.

Due to presence of two unpaired electron in $B_2$ it is paramagnetic in nature.

Since there are no unpaired electrons in $C_2$ it is diamagnetic.

Again, as you can see,since there are no unpaired electrons in $N_2$ it is diamagnetic.

Now, from the diagram, we have to see whether unpaired electrons are present or not.

$B_2$ $⟶$ 2 unpaired electrons

$C_2$ $⟶$ No unpaired electrons

$N_2$ $⟶$ No unpaired electrons

$F_2$ $⟶$ No unpaired electrons

$\Rightarrow$ Unpaired electrons signifies paramagnetic nature.

$\Rightarrow$ Therefore $B_2$ is paramagnetic.