Ernest Rutherford and his students conducted the famous gold foil experiment in 1909, which provided key evidence against the plum pudding model of the atom, proposed by J.J. Thomson. In the plum pudding model, the atom is envisioned as a diffuse cloud of positive charge with negatively charged electrons embedded within it, similar to plums in a pudding.
During the gold foil experiment, Rutherford directed a beam of alpha particles at a thin foil of gold. The results showed that while most of the alpha particles passed through the foil with little to no deflection, a small number were scattered at large angles. This was surprising and indicated that the atom contains a concentrated center of positive charge, which was later identified as the nucleus.
The significant deflections of some alpha particles could not be explained by the plum pudding model, as it implied a uniform distribution of charge in the atom. Instead, Rutherford concluded that atoms consist of a small, dense nucleus surrounded by orbiting electrons, leading to the development of the nuclear model of the atom. This experiment fundamentally changed the understanding of atomic structure and disproved the plum pudding model.
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