The bond order of N2 (nitrogen gas) is 3.
To understand this, we need to look at the molecular orbital configuration of nitrogen. The nitrogen atom has 7 electrons, so a diatomic nitrogen molecule (N2) consists of a total of 14 electrons. The molecular orbital diagram for N2 shows the filling of these electrons in the order of increasing energy levels:
- σ(1s)2
- σ*(1s)2
- σ(2s)2
- σ*(2s)2
- σ(2p)2
- π(2p)2
- π*(2p)0
- σ*(2p)0
So, we can count the number of bonding and antibonding electrons:
- Bonding electrons = 10 (from σ(1s), σ(2s), σ(2p), and π(2p))
- Antibonding electrons = 4 (from σ*(1s) and σ*(2s))
Bond order is given by the formula:
Bond Order = (Number of bonding electrons – Number of antibonding electrons) / 2
This yields:
Bond Order = (10 – 4) / 2 = 3
Therefore, the bond order of N2 is 3, indicating that there are three bonds between the two nitrogen atoms, which contributes to the stability and strength of the N2 molecule.