octet rule

The octet rule is a chemical guideline stating that atoms tend to bond in such a way that they each have eight electrons in their outer shell, resembling the electron configuration of noble gases. This arrangement leads to greater stability. Atoms achieve an octet by sharing, gaining, or losing electrons in chemical reactions—often through covalent or ionic bonding. While not absolute, the octet rule helps explain the behavior of many elements in forming molecules and compounds, especially among the main group elements in the periodic table.