Explanation: Rutherford's alpha-particle scattering experiment was responsible for the discovery of the atomic nucleus. ​Ernest Rutherford was interested in knowing how the electrons are arranged within an atom. Rutherford designed an experiment for this. In this experiment, fast-moving alpha (α)-particles were made to fall on a thin gold foil. He selected a gold foil because he wanted as thin a layer as possible. This gold foil was about 1000 atoms thick. α-particles are doubly charged helium ions. Since they have a mass of 4 u, the fast-moving α-particles have a considerable amount of energy. It was expected that α-particles would be deflected by the sub-atomic particles in the gold atoms. Since the α-particles were much heavier than the protons, he did not expect to see large deflections. But, the α-particle scattering experiment gave totally unexpected results. The following observations were made: Most of the fast-moving α-particles passed straight through the gold foil. Some of the α-particles were deflected by the foil by small angles. Surprisingly, one out of every 12000 particles appeared to rebound On the basis of his experiment, Rutherford put forward the nuclear model of an atom, which had the following features: There is a positively charged centre in an atom called the nucleus. Nearly all the mass of an atom resides in the nucleus. The electrons revolve around the nucleus in circular paths. The size of the nucleus is very small as compared to the size of the atom. Additional Information Electron was discovered by J.J. Thomson in 1896. Sir James Chadwick discovered neutrons in the year 1932. The discovery of the proton is credited to Ernest Rutherford, who proved that the nucleus of the hydrogen atom (i.e. a proton) is present in the nuclei of all other atoms in the year 1917.