What distinguishes the molecular orbital diagram of O2 and F2 from that of Ne2?

The distinction in the molecular orbital diagrams of O2 and F2 compared to Ne2 primarily revolves around the relative energies of the bonding and antibonding molecular orbitals. In O2 and F2, the molecular orbitals are organized in a manner that reflects the energy levels of their electrons according to their respective atomic orbitals. For these diatomic molecules, particularly those in periods 2 and 3, the interactions between atomic orbitals lead to a specific arrangement and energy splitting of the molecular orbitals.

In O2, for example, the π* antibonding orbitals are higher in energy compared to the σ* orbital due to the differences in orbital overlap and stability. This results in the availability of unpaired electrons, which contributes to its paramagnetism. Similarly, in F2, the energy levels reflect the additional electrons but also exhibit a significant energy difference between the orbitals.

On the other hand, Ne2 is a more stable molecule with an even number of electrons filling the bonding orbitals without any unpaired electrons, resulting in a fully filled molecular orbital configuration. The bonding interactions in Ne2 are distinct largely because of the lack of effective overlap due to its higher nuclear charge and paired electrons leading to greater repulsion and a