Physical Science:

The octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a stable configuration of eight valence electrons in their outermost energy level or shell. The rule is based on the observation that elements in the second row of the periodic table (i.e., those with atomic numbers 5 through 10) tend to form stable compounds by gaining, losing, or sharing electrons until they have eight electrons in their outermost shell, which is also called the valence shell. This configuration is known as the octet configuration or the noble gas configuration, and it is particularly stable because it closely resembles the electron configuration of the noble gases in the same row. The octet rule is not a hard and fast rule and there are many exceptions to it. For example, some elements, such as hydrogen and helium, only have a maximum of two electrons in their outermost shell, while some elements in the third row of the periodic table can accommodate more than eight electrons in their outermost shell. Nonetheless, the octet rule provides a useful framework for predicting the likely electron configurations of atoms and the types of chemical bonds that they can form.