The octet rule is important in the creation of chemical compounds because it reflects the basis of what causes the atoms of specific elements to react with each other to form new molecules. The rule describes how chemical bonds are formed and why some elements are highly reactive and others are not. As the name implies, the octet rule is associated with the number "8," which represents the number of electrons present in the outermost electron orbit of an atom in its most stable state.
According to the octet rule, an atom tends to move toward a stable state in which its outermost electron orbit, or valence shell, is filled to capacity with eight electrons. This is the normal and stable state of the noble gases, except for the element helium, which has only two electrons in its outermost electron shell. The noble gas group of the periodic table, which also includes neon, argon and krypton, represents an extremely unreactive group of elements because they don´t fill their valence shells to capacity.
The other elements, however, have less than eight electrons in their valence shells and tend to move toward a chemical reaction with other atoms that will allow them to gain, give up or share electrons so that their outermost shell either contains eight electrons or comes as close as to it as possible. These chemical reactions involve the exchange or rearrangement of electrons between two or more atoms and represent the basis of how chemical bonds are formed between the atoms that combine to create the molecules of compounds.