Types of Intermolecular Forces

Have you ever considered or wondered why liquids tend to flow or solids are sturdy? Or how can we liquify the gases? For understanding these concepts, it is important to study the intermolecular forces of attraction. Hence we must first understand the intermolecular forces and what is meant by the intermolecular force of attraction. The intermolecular forces of attraction can be defined as electrostatic forces between atoms and molecules. 

Every matter that is around us is made up of atoms and molecules. There will always be a force of attraction or repulsion that exists between these atoms and the molecules. The forces within the molecule are responsible for the molecule properties. 

Different Types of Intermolecular Forces

The intermolecular forces can be mainly categorised into two types: attractive forces and repulsive forces. The attraction is primarily caused by the electrostatic forces. However there might be other reasons behind attraction that exists between two or more constituents of the substance. The intermolecular forces of attraction take place between proton of one molecule and electron of another molecule. We will take a brief look at three types of the intermolecular forces.

Dipole-Dipole Interaction

The dipole-dipole interaction consists of the strongest intermolecular forces. These tend to happen only in the polar molecules like HCl. When two of the dipole molecules interact with one another, the negative portion of the polar molecule gets attracted to the positive part of the other molecule. Due to this we get the force of attraction known as dipole-dipole interaction. For instance, HCl is the best example of intermolecular forces in the dipole-dipole interaction. 

Ion-Dipole Interaction

The Ion-Dipole interaction is very similar to the dipole-dipole interaction. The only difference that is observed is the fact that bonds are formed between the polar molecules and ions. For instance, the sodium chloride molecule is an example of the Ion-dipole interaction. When you dissolve NaCl in water, H₂O has polar molecules, and the polar molecules tend to get attracted towards the Cl⁻ and Na⁺ ions. The strength between these forces is based on the strength of the dipole moment and the size of the polar molecule.

Ion Induced Dipole Interaction

When one of the ions is near the nonpolar molecule, it has the capability of polarising it. The non-polar molecule becomes the induced dipole because of the presence of ion. The interaction between the nonpolar molecules and ion is known as the ion induced dipole interaction. The strength of the intermolecular forces depends on the ease with which the polarisation of non-polar molecule happens. 

Conclusion

These are the different types of intermolecular forces you will come across while studying the different topics in physics and chemistry. Focus on the concepts separately and understand the differences properly so that you can determine which intermolecular force is present in an example.