Question

The bond order of NO molecule is

• A. 1.5
• B. 2.0
• C. 2.5
• D. 3.0

Answer 1

The correct option is C 2.5

The total no. of electrons in NO is 15.
Bond order is the number of bonded electron pairs between two atoms.
Bond order =$\frac{1}{2}$[(Number of electrons in bonding molecules) − (Number of electrons in antibonding molecules)]
Molecular orbital configuration of Nitric oxide.

NO: σ$1s^2$ σ∗$1s^2$σ$2s^2$ σ∗$2s^2$σ$2p_z^2$ ($\pi 2p_x^2=\pi 2p_y^2$ ) $({\pi }^{\cdot }2p_x^1={\pi }^{\cdot }2p_y^1)$
Bond order= $\frac{1}{2}$ [ 10-5] = 2.5

So, the bond order of a nitric oxide molecule is 2.5.