The force which holds atoms together in a molecule or a crystal is called a chemical bond.
(2) Metallic Bond:
It is defined as the combination of electrostatic attraction between the electrons and positive nuclei of atoms.
(3) Hydrogen Bond:
It is a dipole attractive forces that exist between two polar molecules, necessary containing a hydrogen atom covalently bonded with an atom of, O or N. Water is its best example. Here Hydrogen bond exists between the Hydrogen atom of one molecule and Oxygen atom of other molecules.