Events
Democritus
The Atom "Atomos"
The atom could not be created, destroyed or further divided.
Broke a shell until it could break no more.Aristotle
Matter is made of Earth, Wind, and Fire
No Empty Space
NO ATOMSJohn Dalton
Studied chemical reactions
Studied mass ratios
CREATED ATOMIC THEORY (Matter is made of atoms)Sir William Crookes
Used Cathode Ray Tubes to conduct experiments
Accidentally discovered electrons (Negatively charged particles)J.J. Thomson
Used Cathode Ray Tubes to conduct experiments
Determined ratio of charge to mass of an electron
Thus discovering there were things smaller than an atomRobert Millikan
Used oil drop apparatus
Discovered the exact charge of an electron (1.602 X10^19)Ernest Rutherford
Using gold foil in a tube
Studied positively charged alpha particles
DISCOVERED NUCLEUS
Created plum pudding model
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