The octet rule is a chemical rule of thumb that reflects observation that atoms of main - group elements tend to combine in such a way that each atom has eight electrons in its valence shell, giving it the same electron configuration as a noble gas. The rule is especially applicable to carbon, nitrogen, oxygen, and the halogens, but also to metals such as sodium or magnesium.
the octet rule states that chemical compounds tend to form so that each atom
has eight electrons in its valence shell, giving it the same electron configuration as a noble gas