Electron - named and discovered by Irish Physicist George Johnstone Stoney, 1891 Proton - named and discovered by New Zealand Physicist and Chemist Ernest Rutherford, 1920 Neutron - discovered by British Physicist James Chadwick in 1932, theorized and named by American Chemist William Draper Harkins in 1921 Quarks - named by American Physicist Murray Gell-Mann, 1964