How do I determine the bond order of Mg2?
The question indicates:
(sigma3s), (sigma3s)*, (pi3p), (pi3p)*, (sigma3p)*; in other words, the (sigma2s) to (sigma2p)* pattern is repeated.
This is the same as a second period diatomic analogous to Be2:
MO diagram with no sp mixing (it doesn’t matter if we have sp mixing or not)
Mg [Ne] 3s^2
Mg2 = 4e⁻= 3σs(2e⁻) 3σs*(2e⁻) 3σp(0) 3πp(0e⁻) 3πp*(0e⁻) 3σp*(0e⁻)
Bond Order = ½[Σ (bonding e-) – Σ (antibonding e-)]
bo = ½[ {σs(2e⁻)} – {σs*(2e⁻)}] = 0
Bond order of mg2