Just out of curiosity,  why are electrons more likely to show up as electron pairs and not a single electron, I think I remember that it is more stable that why, but why is this so? (If there are orbitals of same energy, electrons prefer to stay unpaired, because pairing of electrons works against their electrostatic repulsion. Most often, however, two orbitals have different energies, so both electrons are sitting on the lowest energy one. - GS).   and when would you even find a single lone electron vs. a lone electron pair? (Usually when there is an odd number of electrons, so they just cannot be paired. Also, as I noted above, a particle can have more than one unpaired electron, if it has same in energy (= degenerate) orbitals. - GS). Sorry I know this is more general chemistry but I can’t remember how to justify it.