Question

Among the following, the species having the smallest bond order is:

• A. \( {NO}^- \)
• B. \( {NO}^+ \)
• C. \( {O}_2 \)
• D. \( {NO} \)

Hint:

Use molecular orbital theory to calculate bond orders by subtracting antibonding electrons from bonding electrons and dividing by 2.

Answer 1

The Correct Option is B

Step 1: The bond order of a species is calculated using the molecular orbital theory. The formula for bond order is: \[ {Bond order} = \frac{1}{2} \left( {Number of bonding electrons} - {Number of antibonding electrons} \right). \] 
Step 2: For \( {NO}^+ \), the electron configuration is \( 2 \sigma_g^2, 2 \sigma_u^2, 2 \pi_u^4, 2 \pi_g^2 \), resulting in a bond order of 2.5. 
Step 3: For \( {NO}^- \), the bond order is 2.5, while for \( {NO} \), the bond order is 2.0, and for \( {O}_2 \), the bond order is 2. 
Step 4: The species with the smallest bond order is \( {NO}^+ \) with a bond order of 2.0.