The discovery of the atomic nucleus is attributed to Ernest Rutherford in 1911. He conducted the famous Gold Foil Experiment where he bombarded a thin sheet of gold foil with alpha particles.

He observed that:

* Most alpha particles passed straight through the foil, indicating that atoms are mostly empty space.

* Some alpha particles were deflected at large angles, suggesting the presence of a small, dense, positively charged center within the atom.

Based on these observations, Rutherford proposed the nuclear model of the atom, which stated that:

* Atoms have a tiny, dense, positively charged nucleus at their center.

* Electrons orbit the nucleus in a cloud.

It was Rutherford who coined the term "nucleus" to describe the dense center of the atom.