Subatomic Particles

A Subatomic particle is nothing but a particle which is smaller than an atom in size. Typically, an atom can be broken down into three subatomic particles, namely: protons, electrons, and neutrons.

What are Subatomic Particles?

For a long time, it was believed that atoms are the ultimate particles that matter is made up of and that these atoms cannot be divided further. The experiments conducted during the latter half of the nineteenth century and early years of the twentieth century revealed that even the atom is not the ultimate particle. The continued efforts of the scientists led to the discovery of subatomic particles.

The three primary subatomic particles that constitute an atom are illustrated below.

Subatomic Particles

The limitations of Dalton’s atomic theory to explain certain observations formed the basis for the discovery of electrons and protons. Further investigations revealed the existence of neutrons. The components of atoms are called subatomic particles and generally include the proton, electron, and the neutron.

Discovery and Features of Subatomic Particles

The discovery of the three basic subatomic particles and some of their important features are discussed in this subsection.


Protons and Neutrons together make up the nucleus of an atom and are hence called nucleons. Some important points regarding the discovery and properties of protons are listed below.

  • Protons are positively charged subatomic particles.
  • The number of protons in an atom is equal to the number of electrons in it.
  • The discovery of protons is credited to Ernest Rutherford.
  • Protons can be produced via the removal of an electron from a hydrogen atom.
  • The mass of a proton is 1.676 * 10-24
  • The charge of a proton is +1.602 * 10-19

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Electrons are the subatomic particles that revolve around the nucleus of an atom. These electrons may be removed from or gained by an atom to form ions. Electrons of different atoms come together to participate in chemical bonding. A few points detailing the discovery and the properties of electrons are listed below.

  • Electrons are negatively charged subatomic particles
  • An equal number of electrons and protons are found in the atoms of all elements.
  • J. Thompson is credited with the discovery of electrons since he was the first person to accurately calculate the mass and the charge on an electron.
  • The mass of an electron is negligible when compared to the mass of a proton. It is found to have a mass equal to (1/1837) times the mass of a proton.
  • The charge of an electron is equal to -1.602 * 10-19

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Neutrons, along with protons, make up the nucleons. Neutrons are named for their neutral nature – unlike protons and electrons, they do not carry any charge. The discovery and general properties of neutrons are discussed below.

  • Neutrons are neutrally charged subatomic particles.
  • The masses of two different isotopes of an element vary due to the difference in the number of neutrons in their respective nuclei.
  • The neutron was discovered by James Chadwick in the year 1932.
  • They were discovered in an experiment wherein a thin sheet of beryllium was bombarded with alpha particles.
  • The mass of a neutron is 1.676 * 10-24

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Thus, the discovery and the general properties of the three primary subatomic particles are covered. However, The advances in atomic structure and quantum mechanics have led to the discovery of other fundamental particles. The discovery of subatomic particles has been the base for many other discoveries and inventions.

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Practise This Question

The charge on the electron is-