Final answer:
The expression calculates the bond order in molecular orbital theory, indicating molecule stability and corresponding to single, double, and triple bonds.
Step-by-step explanation:
The expression 1/2 × (number of bonding electrons − number of anti-bonding electrons) represents the bond order in molecular orbital theory. Bond order is a concept used to determine the stability of a molecule, where electrons occupying bonding orbitals stabilize the molecule, while electrons in anti-bonding orbitals destabilize it.
To calculate the bond order, we take the difference between the number of bonding and anti-bonding electrons and divide by two. A positive bond order indicates a stable molecule, and typical bond orders of 1, 2, and 3 correspond to single, double, and triple bonds, respectively.
This formula helps in predicting the relative stability and bond length within molecules.