What is the difference between an intermolecular force and a chemical bond?

1 Answer

Both are distinct concepts that students often get confused.


Chemical bonds are the strong forces that bind atoms to make molecules and compounds. They form when two atoms share or transfer electrons with each other to stay stable. They are INTRAmolecular.

Take NaCl (table salt) as an example.

Na (sodium) has a positive charge (+1), while Cl (chlorine) has a negative charge (-1). To stay stable, both atoms sort of "team up"; the sodium offers to donate its electron, which the chlorine willingly accepts. Therefore both of them have a chemical bond, more specifically an ionic bond.

Another example is CO2 (carbon dioxide). Carbon has 4 valence electrons, and oxygen has 6 valence electrons.

Atoms until the second row are usually happy when they have 8 valence electrons (an exception is hydrogen). So, carbon, and the two oxygen atoms, plan to share electrons among one another; this is a chemical bond called covalent bonds.

One thing to note, intermolecular forces exist between just about everything: atoms, molecules, compounds. However, unlike a chemical bond, which forms when two atoms plan to stay stable, intermolecular forces exist due to molecular polarity.

Water molecules are held together by intermolecular forces; when intermolecular forces are strongest between water, you have ice. When they are medium, you have liquid water. When they are weak, you have water vapor.

Intermolecular forces are easier to break than chemical bonds, and basically come in four varieties (London dispersion, Dipole-Dipole, Hydrogen, Ion-Dipole).

Check this out: http://socratic.org/questions/how-do-chemical-bonds-differ-from-intermolecular-forces-of-attraction