I have observed that when the outermost orbital is half filled (like Nitrogen 1s2 2s2 2p3), the atom has a higher stability (or a lower binding energy). Why is this so? I have heard it has to do with the fact that electron spin is maximized at that point but it still does not make sense to me. Note: Please assume that I have very less knowledge of quantum mechanics. However, I am familiar with electron spin and quantum numbers, the Aufbau rule and the Pauli Exclusion Principle.