jan 1, 1932 - JAMES CHADWICK (1892-1974 CE) date of discovery (1932 CE) Atom is composed of a nucleus containing neutrons (no electric charge) and protons (positively charged) with electrons (negatively charged) orbiting the nucleus at separate levels. Discovered the existence of the neutron by bombarding beryllium with alpha particles. His findings were pivotal to the discovery of nuclear fission and ultimately the development of the atomic bomb.
Added to timeline:
Date:
jan 1, 1932
Now
~ 92 years ago
