Question

The number of bonding electron pairs in $N_2$ on the basis of molecular orbital theory is:

• A. 3
• B. 2
• C. 5
• D. 4

Answer 1

The correct option is C 5

There are 14 electrons in nitrogen. The molecular orbital configuration of molecule will be:
$({\sigma }_{1s}{)}^2,({\sigma }_{1s}^{\ast }{)}^2,({\sigma }_{2s}{)}^2,({\sigma }_{2s}^{\ast }{)}^2,\left[\right({\pi }_{2p_x}{)}^2=\left({\pi }_{2p_y}{)}^2\right],({\sigma }_{2p_x}{)}^2,[({\pi }_{2p_x}^{\ast }{)}^0=({\pi }_{2p_y}^{\ast }{)}^0],({\sigma }_{2p_z}^{\ast }{)}^0$
Thus there are 5 bonding electron pairs and 2 non-bonding electron pairs