1. Matter — Anything that has mass and occupies space is called matter.
2. Intermolecular force — The force of attraction between the molecules of a given substance is called intermolecular force.
3. Element — It is defined as that pure substance which contains only one type of atoms e.g. hydrogen, chlorine.
4. Atom — An atom is the smallest part of an element that takes place in a chemical reaction.
5. Molecule — A molecule is a smallest part of a compound that exists independently.
