Final answer:
The octet rule states that atoms aim to have eight electrons in their valence shell to be as stable as noble gases, mainly achieved through bonds that involve sharing, gaining or losing electrons.
Step-by-step explanation:
The octet rule states that atoms tend to form bonds so that each atom has eight electrons in its valence shell. This rule reflects the observed behavior that elements bond to achieve a valence electron configuration similar to noble gases. Atoms achieve this stable configuration by losing, gaining, or sharing electrons.
When atoms have less than eight electrons in their valence shell, they will often react to form more stable compounds. For example, group 14 elements like carbon can form four covalent bonds to reach a stable octet. However, there are exceptions to the octet rule such as hydrogen, which only needs two electrons in its valence shell, and the transition and inner transition elements that often do not follow the octet rule.
In covalent bonding, nonmetal atoms share electrons such that each atom involved can attain a noble-gas configuration. This-sharing of electrons enables each atom to be considered as having eight valence electrons, except for hydrogen, which aims for two to reach the stability of helium.