Discovery of Protons

In 1886 Eugene Goldstein (1850–1930) discovered evidence for the existence of a positively charged particle. Using a cathode ray tube with holes in the cathode, he noticed that the rays were travelling in the opposite direction from the cathode rays. He called these canal rays and showed that they were composed of positively charged particles. 

The nucleus of the atom was discovered by Ernest Rutherford in the year 1911 in his famous Gold Foil experiment. He concluded that all the positively charged particles in an atom were concentrated in a singular core and that most of the atom’s volume is empty. He also stated that the total number of positively charged particles in the nucleus is equal to the total number of negatively charged electrons present around it. To support his theory he performed a famous experiment known as the Gold foil experiment.

Rutherford Gold Foil Experiment

Rutherford, in his experiment, directed high-energy streams of α-particles from a radioactive source at a thin sheet (100 nm thickness) of gold. In order to study the deflection caused to the α-particles, he placed a fluorescent zinc sulfide screen around the thin gold foil. Ernest Rutherford selected a gold foil for his experiments because he wanted as thin a layer as possible, and gold is highly malleable.

The experimental set-up of the Rutherford Gold Foil experiment is shown below,

Results

The result of his Gold Foil Experiment is,

• Most of the particles pass through the foil without any deflection.
• Some of the alpha particles deflect at small angles.
• Very few particles even bounce back (1 in 20,000).

Conclusion

 Based on his observations, Rutherford proposed the following structural features of an atom,

• Most of the atom’s mass and its entire positive charge are confined in a small core, called the nucleus. The positively charged particle is called the proton.
• Most of the volume of an atom is empty space.
• The number of negatively charged electrons dispersed outside the nucleus is the same as the number of positive charges in the nucleus. It explains the overall electrical neutrality of an atom.

Protons are the fundamental particles that reside inside the nucleus of any atom. They are the positive charge particle and are responsible for balancing the negative charge of the electron to make the atom electrically neutral. Proton was discovered by the famous scientist Ernest Rutherford.

Atoms are made of three fundamental particles Electrons, Protons, and Neutrons. These fundamental particles carry charges such as electrons carrying a negative charge, protons carrying a positive charge and neutrons are neutral in nature.

Let’s learn more about protons, their properties, discoveries, and others in this article. in detail in this article.