Upon completion of this module, you should be able to understand the overlapping of s and p orbitals and know the different types of hybridization. Covalent bonding involves the sharing of electrons between two atoms so that each atom can complete its valence shell. This sharing process occurs through atomic orbitals which are regions of space around the nucleus of an atom where an electron is likely to be found. The valence bond theory states that atoms in a covalent bond share electron density through the overlapping of their valence atomic orbitals.