Class 10 > Unit # 19:Atomic Structure > Basic constituents of an atom

 

Talha's Physics Academy

Basic Constituents of an Atom: Protons, Neutrons, and Electrons

Basic Constituents of an Atom

"Atoms consist of three elemental particles: electrons, protons, and neutrons."

Every atom is fundamentally composed of these three subatomic particles, which determine its mass, charge, and chemical properties:

1. Electrons: Electrons reside in the outermost region surrounding the nucleus, known as the electron shell. They carry a negative charge ($(-1)$). Because an atom typically contains an equal number of protons and electrons, its net electrical charge is zero, making the atom electrically neutral.
2. Neutrons: Located inside the nucleus alongside protons, neutrons carry no net electrical charge (neutral). The mass of a neutron is slightly larger than that of a proton. Protons and neutrons are bound tightly together within the nucleus by strong nuclear forces (mediated by gluons).
3. Protons: Protons reside inside the nucleus and carry a positive charge ($(+1)$) equal in magnitude to the negative charge of an electron.

Properties of Subatomic Particles

The table below summarizes the relative masses and charges of the basic constituents of an atom:

Name of Particle	Relative Mass	Relative Charge
Proton	$1$	$+1$
Neutron	$1$	$0$
Electron	$\frac{1}{1836}$	$-1$

Fig: Distribution of protons, neutrons in the nucleus and orbiting electrons in an atom.

© 2026 Talha's Physics Academy. All rights reserved.