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Democritus proposed that all matter is made up of small particles. Democritus had very little evidence to prove this.
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John Dalton proposed that elements were identical and had the same mass and that compounds were atoms from different elements combined together.
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Faraday developed the two laws of electrochemistry.
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Dmitri Mendeleev created the periodic table.
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Roentgen discovered x-rays.
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J.J. Thomson determined the charge to mass ratio of electrons.
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It showed the the existence of electrons. J.J Thomson helped made this experiment. They did this using a cathode ray tube
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Ernest Rutherford discovered alpha, beta, and gamma rays in radiation.
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Rutherford's Gold Foil Experiment proved the existence of a small massive center to atoms, or as we know as the nucleus.
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Curie discovered radium and polonium
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This experiment measured the elementary electric charge
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Moseley discovered that the number of protons in an element determines its atomic number.
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Bohr proposed an atomic structure theory that stated the outer orbit of an atom could hold more electrons than the inner orbit.
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It consisted of a dense nucleus surrounded by a cloud of electrons at various levels in orbitals.
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Fermi created the first man-made nuclear reactor.
