Intermolecular Forces and Kinetic Theory

All matter is composed of atoms or molecules which are tightly packed or held together in liquids and solids. The forces that hold these atoms or molecules together are called inter-molecular forces. Inter-molecular forces are the greatest in solids, lesser in liquids and least in gases.

Kinetic theory is also termed as ‘thermal motion’. It is related to movement or motion of particles when a substance in any one of the three states of matter is heated.

In solids, as there are strong inter-molecular forces of attraction, the atoms or molecules are fixed. Hence, they vibrate about their mean position.

In liquids, the molecules can move about but they remain in contact with each other.

In gases, molecules move about freely and travel in straight lines until they collide with objects or one another.