According to molecular orbital theory, atomic orbitals combine to form molecular orbital. Number of molecular orbitals are equal to number of atomic orbitals. Further, of the total number of molecular orbitals, half are called as bonding molecular orbital while remaining are anti-bonding molecular orbital. In case, if system contains lone pair of electrons, they occupy non-bonding molecular orbital. Highest occupied molecular energy levels are referred as HOMO, while lowest unoccupied molecular energy levels are referred as LUMO.
In case of B2 molecule, two B atoms combines to generate molecular orbitals. Attached is the MOT diagram of B2 molecule
From the attached figure, it is clearly evitable that high occupied energy level in B2 is π. Also, it must be noted both <span>pi molecular orbitals i.e. Pi 2Px and Pi 2Py at highest energy level (occupied).</span>
In case of B2 molecule, two B atoms combines to generate molecular orbitals. Attached is the MOT diagram of B2 molecule
From the attached figure, it is clearly evitable that high occupied energy level in B2 is π. Also, it must be noted both <span>pi molecular orbitals i.e. Pi 2Px and Pi 2Py at highest energy level (occupied).</span>