What are the electrons that are shared in covalent bonding referred to as?

In covalent bonding, the electrons that are shared between atoms to form a bond are referred to as bonding electrons. When two atoms come close together, they can share one or more pairs of their outermost electrons, which enables them to achieve a more stable electron configuration. This sharing of electrons is essential for the formation of covalent bonds, allowing each atom involved to benefit from the attributes of the other's valence electrons.

Valence electrons are indeed involved in covalent bonding as they are the outermost electrons responsible for chemical bonding, but the specific term for those that are actively shared in the process is "bonding electrons."

Core electrons refer to the electrons in the inner shells of an atom that are not involved in bonding, and free electrons typically suggest those that are free to move, such as in a conductor, rather than being shared between atoms. Thus, bonding electrons specifically describe the shared electrons in a covalent bond, making this terminology the most appropriate choice.