Question

Why is intermolecular forces are electromagnetic in nature?

Answer 1

Not only intermolecular forces but force of friction ,the contact force,spring force and tension in string are electromagnetic in nature .They are produced by the interaction of atoms of two different bodies or in same body in case of tension and spring force, which exert electromagnetic forces on each other. The atoms are composed of charged particles protons and electrons .The atom is normally electrically neutral so cannot exert forces on the atoms of another body kept at some distance . But when two surfaces are in contact the charged particles exert forces on ech other.In case of tension and spring force the interatomic and intermolecular forces cause the atoms to bind together causing a resultant force when a strain is produced in them.For viscous forces, the atoms of the two bodies interact and and electromagnetic forces are applied among the electrons and protons in both the bodies.As the two bodies are in contact the value of such electromagnetic force is significant as the distance between charged particles is very less.