The principle that states that atoms tend to form compounds in which each atom has eight electrons in its highest occupied energy level is called the

The correct answer is the octet rule.

Octet rule states that atoms tend to bond in order to have 8 electrons in their outer most electron orbit achieve stable configurations of noble gases.

When atoms form covalent bonds, they achieve the goal of having 8 electrons by sharing the electrons.

In ionic bond, atom either gain or lose an electron and form ions that have the stable configuration of 8 valence electrons.

Not all atoms follow the octet rule and there are many exceptions and variations.

Exothermic,  physical change after it is already baked