When atoms share electrons to form covalent bonds, the electrons involved in the bonding become delocalized and are no longer associated with a single atom. Instead, these electrons belong to the shared electron pair that exists between the bonded atoms. This means that the electrons are no longer confined to the outermost electron shells of individual atoms but instead occupy the molecular orbitals that result from the combination of atomic orbitals.

In a covalent bond, the electron density is concentrated in the region between the bonded atoms, forming what is known as a covalent molecular orbital. This molecular orbital is a region where the probability of finding the shared electrons is highest. The electrons in a covalent bond are not static and continuously move within the molecular orbital, constantly exchanging positions and occupying different energy states.

The sharing of electrons in covalent bonds allows atoms to achieve a more stable electron configuration, often resembling the electron arrangement of noble gases. This electron-sharing phenomenon results in the formation of stable molecules and compounds with unique properties and characteristics.