Expect the few noble gases, all atoms have less than eight electrons in their valence shell. The octet rule is that those main-group elements typically bind in a way that each atom has eight electrons in its valence shell, giving it the same electrical configuration as a noble gas. The tendency of an element's atom to acquire a stable configuration of eight electrons in its valence shell is known as the Octet rule. Specifically, carbon, nitrogen, oxygen, and halogens are shown octet rule