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400
Aristotle BC
- he thought atoms didn't exist
- all things where made up of earth, fire, water, and air
- he used no method and had no proof
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Dalton 1766
- discovered what atoms were made of
- proposed an atomic theory of matter that become a basic theory of modern chemistry
- gathered evidence from experiments
- atoms looked like billiard balls
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Heisenburg and Schrodinger
- Heisenburg - uncertainly principle
- Schrodinger - mechanics the reason why electrons have
- they used mathematical models
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Thomson 1856
- discovered the electron
- suggested a model of the atom as a sphere of positive matter in electrons in 1904
- nicknamed his model "plum pudding" also "raisin bread"
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Bohr (1885-1962)
- developed a theory about the structure of the atom
- made a model that allow the electrons to be outside the nucleus
- observations of previous models was his method
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Democritus 460 BC-370 BC
- discovered and developed the idea of atoms
- his model was just a round, solid ball
- gathered evidence from experiments
- made a significant contribution with his atomic theory of the universe that all things orginated from atoms.
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Rutherford 1911
- discovered the nucleus
- changed by adding orbiting negative electrons
- mathmatical theories