Who conducted the experiment that provided evidence for a dense nucleus in an atom?

The experiment that provided crucial evidence for a dense nucleus within an atom was conducted by Ernest Rutherford in 1911. Rutherford performed what is known as the gold foil experiment, where he directed a beam of alpha particles at a very thin sheet of gold foil.

During this experiment, he observed that while most alpha particles passed through the foil with little to no deflection, a small number were deflected at large angles. This unexpected result led him to conclude that atoms must have a small, dense, positively charged core, which he termed the nucleus. The significant deflections indicated that not all the mass of the atom could be spread out evenly throughout; rather, there had to be a concentrated point of positive charge that repelled the positively charged alpha particles. This experiment was pivotal in shaping the modern understanding of atomic structure, leading to the planetary model of the atom, where electrons orbit around a central nucleus.