Intermolecular bond: Van der waal and hydrogen bond

Intermolecular force are force that occurs between separate atoms and molecules of different unit.

Intermolecular can be a kind of force that act as attractive or repulsive forces between different unit of atom.

Physical Properties of some compounds like meting, boiling, and conductivity are result from the intermolecular force, how the bond is strong or less strong between the atoms of compound.

There are two major type of intermolecular forces they are

1. Van der waal forces

2. Hydrogen bond

Van der waal forces

This is a type of force that cause week attraction that joining non-polar and polar molecules, and it can be group into two namely

London Dispersion Force

Dipole – Dipole Attraction.

London Dispersion Force

London dispersion force are weak attractions that mainly occurs between non polar molecules , it occurs temporary between the molecules because it can change to  polar when there is constant motion of its electrons that may lead to an uneven charge distribution at an instant.

They occurs between molecules and atoms such as O2, H2, CO2. And they are the weakest

Dipole dipole attraction

Dipole-dipole mainly occurs between the positives end of polar and negative end negative end of another molecules which implies they are more stronger than London dispersion force and occurs between polar (unsymmetrical) molecules. Eg HCL

Dipole dipole attraction can identify when the electronegative between atoms is between 0.4 and 1.7 then it polar molecules and the type of attraction between them will be dipole dipole attraction.

Hydrogen bond

Hydrogen bonds are more stronger than Van der waal forces it is the special dipole attraction that also occurs between polar molecules, when hydrogen atom is covalently bonded to a highly electronegative atom such as O N CL

The higher the electronegative of an electronegative atoms the higher the hydrogen bond strength.

Hydrogen bond also result in physical changes of some molecules such as H2O.