4.2 Structure of Atoms

1. All matter consists of tiny units called atoms.
2. Atom is a basic unit of all matter.

4.2.1 Subatomic Particles
1. An atom is made up of particles that are even smaller called subatomic particles.
 There are three types of subatomic particles, which are
 (a)  Protons
 (b)  Neutrons
 (c)  Electrons

Subatomic particles in an atom

4.2.2 Comparison between Subatomic Particles

Atoms of any element are neutral because the number of protons and the number of electrons in an atom are the same.
2. In a neutral atom, the number of protons is the same as the number of electrons.