The electrons involved in the formation of a chemical bond are called

Valence electrons

Valence electrons are those that are in the outermost or superficial layer of the atom, which means they have the highest energy compared to those of the inner layers.

Because of their position, it is easier for these electrons to interact with other atoms of their own element as well as different elements. This is done through the process of forming bonds when being attracted by other atoms.

when it gains or loses electrons