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.
Not all of the electrons in an atom make chemical bonds. Most atoms form bonds using only the electrons in the outermost energy level. An electron in the outermost energy level of an atom is a valence electron. The models in Figure 3 show the valence electrons for two atoms. Figure 3 Counting Valence Electrons