Which sub-atomic particle was discovered by

(a) Thomson (b) Goldstein (c) Chadwick.

(a) Thomson in 1897 was the first to suggest that one of the fundamental units was more than 1,000 times smaller than an atom, suggesting the subatomic particle now known as the electron. Thomson discovered this through his explorations on the properties of cathode rays.

(b) Eugen Goldstein was an early investigator of discharge tubes, the discoverer of anode rays, and is sometimes credited with the discovery of the proton.

(c) Chadwick found the neutron by hitting a chemical called beryllium with alpha particles.