Involves the valence electrons.

Valence electrons are the outermost electrons in an atom that are involved in chemical bonding. They play a crucial role in determining the reactivity and chemical properties of an element. Valence electrons can be shared, transferred, or involved in forming chemical bonds with other atoms to achieve a stable electron configuration. The number of valence electrons in an atom dictates how it will interact with other atoms and determines its ability to form chemical bonds.