Protons - The Fundamental Sub-Atomic Particle

What are Protons?

Protons are the positively charged particles which are present in the nucleus of an atom.

An atom is composed of protons, electrons, and neutrons. The entire mass of an atom is concentrated in the nucleus which is at the centre. The nucleus contains protons and neutrons which are collectively called nucleons. Electrons revolve around the nucleus in circular orbits.

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What is the Mass of Proton?

The mass of a proton is 1.6726219 × 10-27 kilograms

Protons are positively charged particles, electrons are negatively charged and neutrons have no charge. In an atom the number of protons and electrons are equal. Thus an atom is electrically neutral in nature.

Protons – The Fundamental Sub-Atomic Particle

Discovery of a Proton

Goldstein in the year 1886 found that the charge to mass ratio of the positive particles depends on the nature of the gas which is present in the discharge tube. This means that the charge to mass ratio (e/m) was different for different gases.

He observed that the charge to mass ratio of the positive rays was highest in case of the hydrogen gas that was used in the discharge tube. This is mainly because hydrogen is the lightest atom so mass will be the least hence e/m ratio will be highest in this case.

The particle in the positive rays in the discharge tube was named as a proton. A proton can be produced when we remove an electron from the hydrogen atom.

H (hydrogen atom) → H+   (proton) +   e (electron)

Thus, it can be said that a proton is a hydrogen ion (H+).

Properties of Protons

Proton is a positively charged particle and has the following physical properties:

  1. Mass of Proton – The mass of a proton is equal to that of the hydrogen atom. A hydrogen atom consists of one electron and one proton. As the mass of an electron is considered to be negligible therefore it can be said that the mass of a hydrogen atom is equal to the mass of a proton. The mass of a proton is 1840 times the mass of an electron.
Mass of proton = 1.676 × 10-27 kg = 1.676 × 10-24 g = 1.6726219 × 10-27 kg
  1. Charge of Proton – The charge of a proton is equal to and opposite to that of an electron. Thus, it has a unit positive charge.
Charge on a proton = + 1.602 × 10-19 coulombs

Frequently Asked Questions


Do electrons have mass?

An electron is considered massless when compared with a neutron and proton. Also, the mass of an electron is not considered while calculating the mass number for an atom.


Who is the father of Proton?

Ernest Rutherford is the father of Proton.


What is inside a proton?

The proton, one of the atomic nuclei parts, consists of three quarks which are held together by gluons.


Who discovered the proton and through what experiment?

Rutherford found proton in his famous experiment on gold foil in 1909.


What is electron proton neutron?

Atoms consist of small particles called protons, neutrons, and electrons. The nucleus is made up of protons and neutrons in the middle of the atom. The nucleus is surrounded by electrons. Protons are charged positively. Electrons are charged negatively.

The properties and discovery of a proton are briefly described in this article. For more content on the mass of proton register to BYJU’S.

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  1. Is mass of proton always equal to mass of hydrogen?

    • The mass of a proton is almost equal to that of a hydrogen atom (the mass of hydrogen is slightly higher since it also contains an electron).