Rutherford's a-particle scattering experiment on gold foil is responsible for the discovery of :

Rutherford's alpha-particle scattering experiment, conducted in 1911, led to the discovery of the atomic nucleus [1]. By bombarding a thin gold foil with alpha particles, Rutherford observed that while most particles passed through, a small fraction was deflected at large angles or bounced back [1]. This evidence contradicted the prevailing 'plum pudding' model and suggested that the atom's positive charge and nearly all its mass are concentrated in a tiny, dense central region. Rutherford termed this central core the 'nucleus'. While he later identified the proton as a component of the nucleus, the gold foil experiment specifically established the existence of the nucleus itself [3]. Other subatomic particles like the electron and neutron were discovered by J.J. Thomson and James Chadwick, respectively.

Sources

1. [1] https://www.fnal.gov/pub/inquiring/timeline/03.html
2. [3] https://www.khanacademy.org/a/discovery-of-the-electron-and-nucleus