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Democritus proposed that the world is made of empty space and tiny particles called atoms. He thought that atoms were the smallest particles of matter. He created the Atomic Theory.
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Aristotle believed that all matter was made of 4 elements which are fire, earth, air, and water
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Lavoisier created the Law of Conservation.
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Dalton discovered that all matter is made of atoms. All atoms that make up the element have the same mass.
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Avogadro believed that equal volumes of different gases contain an equal number of molecules- Avogadro hypothesis
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He made a table of atomic weights which included 43 elements.
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Mendeleev created the Periodic Table of Elements
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Thomson discovered the electron while experimenting with cathode-ray tube. He discovered that the model of the atom was spherical with electrons surrounding it. He made the Plum Pudding Model.
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Goldstein discovered the proton
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Schrodinger suggested that the atom had an electron wave like an orbit- Electron Cloud Model. He also introduced wave mechanics.
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Moseley developed the X-ray spectra to study atomic structures. He found out that the atomic number of an element is equal to the number of protons in the nucleus.
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Chadwick discovered the neutron.
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Becquerel discovered radioactivity.
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Curie discovered radium and polonium and coined term radioactivity
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Planck is credited for describing hot glowing matter using quanta. Created the Quantum Theory.
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Rutherford conducted the Gold Foil experiment which proved the existence of a nucleus, the Rutherford Model.
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Bohr created the Bohr Planetary Model which was inspired by the fact that gravity pulls things together. He developed a way to explain atomic structure using the Periodic Table of Elements.
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Millikan proved Albert Einstein's law describing photoelectric phenomenon. He discovered the charge of a electron.
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The Quantum Mechanical Model is the most recent model we hold as standard today
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Heisenburg proposed the principle of Indeterminacy. It means that you can't know the position and velocity of a particle.
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Meitner helped discover nuclear fission.
