What is the octet rule?

The octet rule states that atoms tend to strive for a full valence shell of eight electrons to achieve stability. This tendency arises from the observation that many elements, particularly those in the main groups, are most stable when they have a complete outer electron shell, akin to the electron configuration of noble gases, which naturally have filled valence shells.

When atoms have eight electrons in their outermost shell, they attain a more stable and energetically favorable state. This often influences how they bond with other atoms, leading to the formation of stable compounds through ionic or covalent bonding.

In contrast, the other choices do not accurately depict the essence of the octet rule. While it is true that some atoms prefer an even number of electrons or that they can bond with others, these aspects do not capture the central idea of achieving eight electrons in the valence shell for stability. Similarly, the flexibility in losing or gaining electrons is more a description of atom behavior than a principle central to the octet rule.