-
Democritus
460 BC
- Developed idea of the atom.
- Called them "Atoma" Meaning invisible in greek. -
Aristotle
460 BC
-Thought entire universe is made up of 5 elements.
-Matter is NOT made up of tiny particles. -
John Dalton
1808
-All matter made up of tiny spheres, able to bounce around , called atoms. -
J.J. Thompson
1898
-Atom has a negative charge
-Created "plum pudding" model -
Robert Millikan
1908
-Performed "oil-drop" experiment
-Said an electron = 1.59X10(-19) -
Ernest Rutheford
1910
-"Gold Foil" expirement
-Most mass is in mucleus
-created nuclear model
