What are valence electrons?

Valence electrons are defined as the outer shell electrons of an atom. These are the electrons that reside in the highest energy level and are primarily responsible for the chemical properties of the element and its ability to form bonds with other atoms. The outermost shell of an atom determines its reactivity; for instance, elements with a full valence shell are generally non-reactive, while those with one or more unpaired valence electrons tend to be more reactive.

In contrast, electrons in the nucleus are not relevant to this definition, as valence electrons pertain only to those in the outer energy levels. Similarly, while electrons that can carry current are indeed important in the study of electricity, this description encompasses a broader range of electrons, not limited to valence electrons specifically. Protons, which are positively charged particles located in the nucleus, have no relation to valence electrons since they are not electrons but rather a different kind of subatomic particle entirely.