Protons-The Fundamental Sub-Atomic Particle, Discovery, Properties, Subatomic (For CBSE, ICSE, IAS, NET, NRA 2022)

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What Are Protons?

  • Protons are the positively charged particles which are present in the nucleus of a hydrogen 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.

What is the Mass of Proton?

The mass of a proton is

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.

Mass of Proton

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 m 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.

Thus, it can be said that proton is a hydrogen ion .

Properties of Protons

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

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 hydrogen atom is equal to the mass of a proton. The mass of a proton is 1840 times the mass of an electron.

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.

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 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.

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