The bond order in the NO molecule is
A) 3
B) 2
C) 2.5
D) 1
E) 1.5

Question

Quizplus · Accepted Answer

The bond order of the NO molecule can be calculated using the formula:
Bond order = (number of bonding electrons – number of antibonding electrons) / 2 
In NO, there are 5 valence electrons of nitrogen (2s2 2p3) and 6 valence electrons of oxygen (2s2 2p4), making a total of 11 valence electrons. We can draw the molecular orbital diagram for NO as follows:

|---------------------------|
 σ* (2p)  |   ↑   ↓            |
|---------------------------|
 π* (2p)  |   ↑   ↓            |
|---------------------------|
 σ (2p)   |   ↑   ↓            |
|---------------------------|
 π (2p)   |  ↑ ↓ ↑ ↓           |
|---------------------------|
 σ (2s)   |  ↑↓             |
|---------------------------|

In this diagram, there are 5 bonding electrons and 2 antibonding electrons. Therefore, the bond order of NO is:

Bond order = (5 – 2)/2 = 1.5

Therefore, the best choice is C.

The Bond Order in the NO Molecule Is