What are the electrons in the outermost energy level of an atom called?

The electrons in the outermost energy level of an atom are called valence electrons. Valence electrons are crucial because they play a key role in chemical bonding and reactions. Atoms tend to interact with each other by gaining, losing, or sharing these electrons in order to achieve stability, often seeking a full outer shell according to the octet rule.

Valence electrons determine the chemical properties of an element, including its reactivity and the types of bonds it can form with other atoms. For instance, elements in the same group of the periodic table typically have similar valence electron configurations and, consequently, similar chemical behavior.

The other terms do not apply to the outermost electrons in the same way. Inner electrons refer to electrons that occupy the inner shells and are not involved in bonding. Core electrons are often used interchangeably with inner electrons, denoting those that are not in the valence shell. Atomic electrons is a broader term that could refer to any electrons within the atom but does not specifically identify those involved in chemical interactions. Thus, the term “valence electrons” is the most accurate descriptor for the electrons in the outermost energy level.