Introduction
Intermolecular forces are the forces that hold molecules together and are responsible for the physical properties of a substance. They are weaker than the intramolecular forces that hold atoms together in a molecule, but they are still very important in determining the properties of a substance. In this blog post, we will look at the different types of intermolecular forces and rank them from the strongest to the weakest.
London Dispersion Forces
London dispersion forces (LDFs) are the weakest type of intermolecular force, but they are also the most common. They are caused by the temporary dipole-dipole attractions that occur between two non-polar molecules. These attractions are caused by the random fluctuations in electron density that occur in the molecules. These forces are very weak, but they can still have a significant effect on the properties of a substance.
Van der Waals Forces
Van der Waals forces (vdW) are slightly stronger than LDFs and are caused by the electrostatic interactions between molecules. These forces are caused by the temporary dipole-dipole attractions between two molecules and can be either attractive or repulsive. These forces are responsible for the physical properties of a substance, such as its boiling point and melting point.
Hydrogen Bonding
Hydrogen bonding is the strongest type of intermolecular force and is caused by the electrostatic interactions between a hydrogen atom and an electronegative atom, such as oxygen or nitrogen. These forces are very strong and are responsible for the boiling points and melting points of substances. They are also responsible for the formation of water molecules and the structure of proteins.
Dipole-Dipole Interactions
Dipole-dipole interactions are slightly weaker than hydrogen bonding, but they are still very important in determining the physical properties of a substance. These forces are caused by the electrostatic interactions between two molecules that have permanent dipoles. These forces are responsible for the boiling points and melting points of substances and are also responsible for the formation of crystals.
Hydrophobic Interactions
Hydrophobic interactions are the weakest type of intermolecular force and are caused by the repulsion between non-polar molecules and water molecules. These forces are responsible for the formation of micelles and the structure of proteins.
Conclusion
Intermolecular forces are the forces that hold molecules together and are responsible for the physical properties of a substance. They range from the weakest, London dispersion forces, to the strongest, hydrogen bonding. Each type of intermolecular force has its own unique effects on the physical properties of a substance and is responsible for the formation of molecules and the structure of proteins.
