What is the roal of neutrons Who discovered it how .explain Rutherford S experiments

Neutrons contribute to half the mass of the nucleus. It was discovered by James Chadwick.He bombarded a think foil of beryllium with fast moving alpha particles and observed that highly penetrating rays consisting of neutral particles were present. Rutherford experiment showed that most of the space in an atom is empty and all the mass of the atom is concentrated in the nucleus and the electrons revolve around the nucleus like planets