The flashcards below were created by user
kelly
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Democritus
atoms = indivisible
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Aristotle
- matter is continuous and can be divided infinitely into smaller particles
- was wrong
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Antoine Lavoisier
law of conservation of mass
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Joseph Proust
law of definite proportions (ratio is always going to be 2 H to 1 O)
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Dalton
- atomic theory
- 1. law of multiple proportions (CO, CO2) / law of definite proportions (formula)
- 2. all elements are made up of indivisible atoms (WRONG)
- 3. law of conservation of mass
- 4. atoms of one element differ in properties from atoms of another element
- 5. all atoms of a give element are the same (WRONG b/c of isotopes)
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Crooke
- Crooke's tube (cathode ray tube)
- rays deflected away from negatively charged magnet--> cathode rays are negatively charged particles
- discovered electron
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Thomson
- discovered proton
- determined ratio of charge to mass
- Plum Pudding Model
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Millikan
- Oil Drop Experiment
- measure charge of electron
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Rutherford
- Gold Foil Experiment
- bombarded gold foil with positively charged alpha particles
- most went through foil, but few were deflected
- atom mostly empty space
- nucleus = dense core with positive charge
- knew there was another particle in nucleus b/c mass was too large
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Chadwick
discovered neutrons
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Marie Curie
discovered radiation
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nuclear force
optimum distance for attraction between forces in nucleus
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electrostatic attraction
attraction between electron and proton
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