The allegory not only draws on the theory of forms, but it is connected both to the concept of forms and Plato's theory of the stages of life. 1  At the lowest stage, the cognitive stage of imagination (in Greek, eikasia), the prisoners exist bound and hindered in their perspective.
Since any orbital can hold a maximum of two electrons, the bonding orbital in H 2 + is only half-full. This single electron is nevertheless enough to lower the potential energy of one mole of hydrogen nuclei pairs by 270 kJ quite enough to make them stick together and behave like a distinct molecular species.
Because space has 3 dimensions and electrons have spin Â½. The most tightly bound electron in an atom has zero orbital angular momentum. But because of the spin, there are two ways to put an electron into that orbit: spin up and spin down. That means you can put 2 electrons into the most tightly bound orbit.