Solution:
The bond order of a molecule can be calculated using the following formula:
Bond order = (number of bonding electrons - number of anti-bonding electrons) / 2.
where a bonding electron is an electron present in a bonding orbital, and an anti-bonding electron is an electron present in an anti-bonding orbital.
- N2 has 14 valence electrons, with 6 electrons in the bonding orbitals and 4 electrons in the anti-bonding orbitals. Bond order of N2 = (6 - 4) / 2 = 1
- O2 has 16 valence electrons, with 8 electrons in the bonding orbitals and 4 electrons in the anti-bonding orbitals. Bond order of O2 = (8 - 4) / 2 = 2
- O2+ has lost an electron, so it has 15 valence electrons. There are 8 electrons in the bonding orbitals and 3 electrons in the anti-bonding orbitals. Bond order of O2+ = (8 - 3) / 2 = 2.5
- O2- has gained an electron, so it has 17 valence electrons. There are 8 electrons in the bonding orbitals and 5 electrons in the anti-bonding orbitals. Bond order of O2- = (8 - 5) / 2 = 1.5
Therefore, the bond order of N2 is 1, the bond order of O2 is 2, the bond order of O2+ is 2.5, and the bond order of O2- is 1.5.