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12 Cards in this Set
- Front
- Back
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Democretus
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-greek philospher/scientist
-believed all matter was made of indivislbe particles (later: atoms) |
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Robert Boyle
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-defined the term element: substance that can't be broken in to a smaller substance
-determined average body temperature |
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Antonie Lavosier
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-the "pioneer of modern chemistry"
-first to use careful and controlled experiments -worked with metals and oxygen -determined the LAW OF CONSERVATION OF MASS: during a chemical reaction, matter is neither created nor destroyed |
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Joseph Proust
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-published the LAW OF DEFINITE PROPORTIONS aka LAW OF CONSTANT COMPOSITIONS: a compound is composed of exact proportions of elements by mass regardless of how or where the compound was created
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John Dalton
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took the def. of elements, law of conservation of mass, law of constant composition, then came up with theory
DALTON'S ATOMIC THEORY 1. all elements are composed of atoms, atoms are indivislbe & indestructable (false) 2.All atoms of the same element are identical (false) 3.Atoms of different elements are not the same 4.Atoms retain their identity in chemical reactions 5.Compounds are formed by joining atoms in specific whole number rations |
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Michael Faraday
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-worked with electrolytes
-passed electricity through solution of zinc chloride. He believed something was passing through the solution. He called it the electron. He didn't know what they were or how they behaved. |
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Joe John Thompson
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-worked with the Crooks Tube & cathode rays. The cathode rays could be electrons.
-his experiments showed the - end of magnet repelled cathode ray, + end attracted cathode ray. -concluded: A) cathode ray was composed of electrons. B)the electrons have a negative charge. C) changed experiment with different metals, same result. D)finding the first subatomic particle, it was composed of all matter. |
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Lord Kelvin
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-proposed new model based on Thompson's experiment
-got the idea from plum pudding. He figured if there are (-)'s there must be (+)'s. The electrons are scattered in a sea of (+)'s |
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Robert Milikan
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-determined the mass of the elctrons as 9.11 x 10^-31 kg
-used experiment with charged oil dropplets |
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Henri Becquerel
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-discovered Nuclear radiation in 1896.
-stored U compounds in his desk drawer with photography paper -when he developed the film, he saw an image of rock on the film. The compound exposed itself on the photo paper through protective coating. |
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Marie Curie
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-started working with U, wanted to know about its "radioactivity"
-lead to discovery to the neutron. -Discovered Polonium and Radium with her husband |
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Ernest Rutherford
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-one of Thompson's students, wanted to disprove plum pudding mode.
-set up the gold foil experiment. He expected the alhpha particle would move straight through the gold foil. 1 in 20,000 alpha particles bounced off the gold foil. He hypothesized most of the atom was empty space. -He led to the discovery of the nucleus of the atom. |
