Ernest Rutherford's experiments, specifically the famous gold foil experiment, played a crucial role in deducing the structure of the atom and the presence of a nucleus around which electrons revolve. Here's a summary of how Rutherford arrived at this conclusion:
Alpha particle scattering: Rutherford directed a beam of alpha particles (positively charged particles) at a thin sheet of gold foil. According to the prevailing "plum pudding" model proposed by J.J. Thomson, the atom was thought to be a diffuse, positively charged mass with negatively charged electrons embedded within it.
Unexpected results: Rutherford and his team expected the alpha particles to pass through the gold foil with only minor deflections due to the Thomson model. However, they observed that a small fraction of the alpha particles were significantly deflected at large angles, and a few even bounced straight back.
Conclusion: Rutherford reasoned that the unexpected deflections and backscattering of alpha particles could only be explained if the positive charge and mass of the atom were concentrated in a small, dense region within the atom, which he called the nucleus. He proposed that the rest of the atom was mostly empty space with electrons orbiting around the nucleus.
Nuclear model of the atom: Based on his observations, Rutherford developed the nuclear model of the atom, in which the nucleus contains positively charged protons and uncharged neutrons, while the negatively charged electrons orbit around the nucleus. The nucleus was presumed to be extremely small compared to the overall size of the atom.
Rutherford's experiments provided crucial evidence that led to a significant shift in the understanding of atomic structure, eventually paving the way for the development of quantum mechanics and a deeper understanding of the subatomic world.