Molecular Attraction – Why Do Two Molecules of an Element Attract?

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I was thinking about molecular attraction and a question suddenly struck in my mind which is 'Why do two molecule of an element attract each other?'

The answer is easy when we discuss about compound materials. The molecules of a compound have dipoles that can attract each other. But what happens about elements? The molecules of an element don't have dipoles.

After so many attempts, I thought there are only two particles in those molecules that can attract each other — Neucleus and Electron. But also there works repulsive forces between the electrons and between the neucleus of two molecules. It seems like the repulsion is stronger attraction.

So how the attraction force get stronger than the repulsion force so that two molecules of an element attract each other?

Best Answer

There are only seven elements which naturally form stable molecules, namely hydrogen, oxygen, nitrogen, fluorine, chlorine, bromine and iodine. At room temperature only iodine is a solid. When they do liquify or solidify, they do so as a result of Van Der Waals forces, which are electromagnetic in nature, acting at short range between the individual molecules. See https://en.wikipedia.org/wiki/Van_der_Waals_force

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