Chapter 5, Problem 5.69CHP

Interpretation Introduction

Interpretation:

The molecular orbital diagram for ${\text{Li}}_{\text{2}}$, its bond order and its stability has to be explained.

Concept introduction:

Molecular orbital theory:

• The atomic orbitals of the atoms constituted in a molecule are combined to produce new orbitals are called Molecular Orbitals.
• Like atomic orbitals, a molecular orbital can accommodate maximum two electrons and the two electrons must have opposite spins (Pauli Exclusion Principle).
• The numbers of MO’s are equals to the number of atomic orbitals are combined in such a way that the linear combination of similar atomic orbitals to form one bonding and one anti-bonding MO’s.
• The bonding MO’s are lower in energy than the anti-bonding MO’s.
• HOMO is the highest energized occupied orbital in the MO’s.
• Relative energy levels of molecules are according to the energy levels of atomic orbitals.
• LUMO is the lowest energized orbital in the MO’s.

  $\text{Bond}\text{order}\text{=}\frac{\text{1}}{\text{2}}\left[\left(\begin{array}{l}\text{number}\text{of}\text{electrons}\text{in}\\ \text{bonding}\text{molecular}\text{orbitals}\end{array}\right)\text{-}\left(\begin{array}{l}\text{number}\text{of}\text{electrons}\text{in}\\ \text{antibonding}\text{molecular}\text{orbitals}\end{array}\right)\right]$