Democritus was a Greek scientist that hypothesized the existence of atoms and their being indivisible and indestructable.
384 B.C. - 322 B.C.
Aristotle was a Greek scientist that rejected Democritus' idea as he thought that matter was continuous.
1766 - 1844
Dalton was a English scientist that came up with the atomic theory
1832 - 1919
Crookes was a British scientist that developed the cathode ray tube
1856 - 1940
Thompson was a British scientist that showed that the "cathode ray" which traveled from cathode(-) to anode (+) was electrons in 1897. Thompson also discovered electrons and developed the plum pudding model.
1863 - 1953
Millikan was an American scientist that found the charge on an electron to be 1.602 x 10^ -19 Coulobmbs and found the mass of an electron to be 9.11 x 10^ -28
1871 - 1937
Rutherford was an English scientist that conducted the gold foil experiment which led to the concept of the nucleus. Therefore, Rutherford discovered the nucleus and also developed the nuclear model.
1885 - 1962
Bohr was a Danish scientist that found that hydrogen absorbs energy then releases it at a specific frequency
1887 - 1915
Moseley was an English scientist that found that atoms have a special and unique charge
1891 - 1974
Chadwick was an English scientist that discovered the existence of neutrons.