The fundamental particles present in the nucleus of an atom are
(1) Electron, proton
(2) Proton, neutron
(3) Neutron, electron
(4) Neutron, positron
Answer: (2) The nucleus is the very dense region consisting of protons and neutrons at the center of an atom. It was discovered in 1911 as a result of Ernest Rutherford’s interpretation of the famous 1909 Rutherford experiment performed by Hans Geiger and Ernest Marsden under the direction of Rutherford. The proton-neutron model of the nucleus was proposed by Dmitry Ivanenko in 1932. Almost all of the mass of an atom is located in the nucleus, with a very small contribution from the orbiting electrons.
