Intermolecular forces are the forces that exist between molecules. There are three main types of intermolecular forces:
- Dispersion Forces (London Forces): These are the weakest intermolecular forces that arise due to temporary fluctuations in electron distribution within molecules. Even in nonpolar molecules, these temporary dipoles can induce a dipole in neighboring molecules, leading to a very weak attraction.
- Dipole-Dipole Forces: These occur between polar molecules where the positive end of one polar molecule is attracted to the negative end of another. This force is stronger than dispersion forces and plays a significant role in determining the boiling and melting points of polar substances.
- Hydrogen Bonding: Although technically a part of dipole-dipole interactions, hydrogen bonds are strong attractions that occur when hydrogen is covalently bonded to highly electronegative atoms such as nitrogen, oxygen, or fluorine. These bonds are particularly significant in biological molecules, like DNA and proteins, influencing their structure and function.
Understanding these forces helps explain various physical properties of substances, such as boiling and melting points, viscosity, and solubility.