1 jan 1826 ano - James Chadwick

Descrição:

He discovered the Neutron in atoms. Neutrons are located in the center of an atom, in the nucleus along with the protons. They have neither a positive nor negative charge, but contribute the the atomic weight with the same effect as a proton.

Experiment- Projecting alpha particles toward Beryllium "the light element". The emitted particles after enduring the Beryllium target (become neutrons) and fall on the paraffin wax.The paraffin wax in turn releases another type of particle (protons).