Molecular Orbital Energy Diagrams

Molecular orbital theory- The molecular orbital theory or the MOT is a way of explaining the electronic structure of atoms and molecules using quantum mechanics. The basic principle of this theory is that as atoms bond to form molecules, a particular number of atomic orbitals merge to create the same number of molecular orbitals, although the electrons entangled may be redistributed among the orbitals. The MO theory is appropriate for simple diatomic molecules such as dihydrogen, dioxygen, and carbon monoxide. However, it becomes difficult while discussing polyatomic molecules, such as methane.

Homonuclear species- A homonuclear molecule is a molecule that contains only one element. It may have various numbers of atoms of the same element. 

Diatomic species – A diatomic molecule is a molecule that has two molecules of the same or different elements.

Homonuclear diatomic species-A homonuclear diatomic molecule is a molecule that has two atoms of the same element—for example, H2, O2, and N2.

MO diagrams

In a Molecular orbital energy diagram, horizontal lines are in the centre, forked by constituent atomic orbital energy levels. The energy levels increase from the bottom to the top. A diatomic molecular orbital diagram helps us deduce the magnetic properties of the molecule, changes during ionization, bond order, and the number of bonds formed. Following are the MO diagrams of some homonuclear diatomic species.