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Period: 400 to
History of Atom
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450 - Democritus (400B.C.)
- discovery: 400 B.C.
- that atoms can be broken into smaller parts.
- he has does not have any evidence to support his theory.
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Aristotle
- 450- (340 B.C.)
- matter is made up of the these elements: earth, air, fire, and water
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Dalton
-1808 A.D.
- matter was made up of atoms
- method: used experimental methods to recontruct Democritusi ideas -
Thompon
- 1897 A.D.
- using cathode ray, that there seemed to be negatively charged particles in atoms making them able to be split even further apart
- method: cathode ray rubes
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Rutherford
- 1909 A.D.
- he discovered the nucleus, and found that inside was a postively charged particle (called a proton)
- method: Gold- Foil experiment
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Bohr
1913 A.D.
electrons travled in shells, or certain energy levels around the nucleaus -
Heisenberg & Schrodinger
- the equations
