Summary:
- A covalent bond forms when the electron clouds of two atoms overlap with each other.
- In a simple H2 molecule, the single electron in each atom becomes attracted to the nucleus of the other atom in the molecule as the atoms come closer together.
- The overlapping orbitals do not have to be of the same type.
- In valence bond theory, the electrons in a molecule are assumed to occupy atomic orbitals of the individual atoms and a bond results from overlap of those orbitals.
- This idea forms the basis for a quantum mechanical theory called valence Bond (VB) theory.