Question

What are the subatomic particles contained in the nucleus of an atom?

Answer 1

Hint: An atom is the smallest particle in an atom until we found there are more fundamental particles of matter. Bohr was the first one to devise that the atoms can further be differentiated into subatomic particles and these particles have charge and the nucleus is at the centre of it and around the nucleus electrons revolve.

Complete step by step answer:
On discovery of electrons by faraday in his cathode ray tube, there were speculations that for the atom to be stable there must be some other charge present there to balance the charge on the atom.
Protons were discovered by Rutherford in $1919$ and it started to appear in Rutherford atomic models first. Then an electrical discharge carried out in the modified cathode ray tube led to the discovery of canal rays which were basically positively charged rays, confirming the presence of positively charged subatomic particles.

Neutrons were discovered by Chadwick in $1932$, while on bombarding a thin sheet of beryllium by alpha particles, neutrally charged particles were discovered which had mass much greater than that of the positive particle.

The positive subatomic particle was named proton while the neutrally charged particle is called the neutron. After Rutherford’s model, we also knew about the existence of a nucleus containing positive charges.

The subatomic particles contained in the nucleus of an atom are proton and neutron.

Note: The total charge on an atom always remains zero, therefore the number of electrons present in an atom is always equal to the number of protons which is called atomic number while the sum of neutrons and protons is called the mass number.