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Democritus said everything was composed of atoms and were constantly moving. He also claimed they are infinite in number and indestructible.
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This law claimed that matter is not created nor destroyed in a closed system.
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Lavoisier discovered matter was composed of atoms that aren't created or destroyed during chemical reactions.
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Alchemists believed that all metals were made up of mercury and sulfur.
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This law claims every chemical compound has a set proportion of the elements it contains.
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Dalton's theory said all matter is made up of atoms. These atoms are indivisible.
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Dalton's theory had 3 parts, all matter is made of atoms, all atoms of a given element are identical in mass and properties, and compounds are combinations of two or more different types of atoms.
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Proust suggested all matter was composed of tiny indivisible particles, called atoms. He also created the Law of Definite Proportions.
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Mendeleev found that when all known chemicals are arranged in order by increasing atomic weight there is a pattern. The pattern has periodicity within the groups of elements.
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Thomas discovered the electron, disproving the theory that atoms were the smallest particle to exist.
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The Cathode Ray Tube experiment proved the ray was composed of negatively charged particles. Then that these particles must exist as part of atoms found in every element.
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This model gave the theory that claimed the atom had a negatively charged electrons with a positive "soup" around.
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Millikan confirmed the existence of the electron and determined it's charge.
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This experiment determined that electrons have mass and a specific charge.
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The Gold Foil experiment proved the atom has a positively charged nucleus. This nucleus is tiny, dense, and mostly empty space.
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Rutherford's nuclear model showed there is a nucleus inside an atom, the electrons are distributed around this nucleus.
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Rutherford conducted the gold foil experiment showing that an atom is a mostly empty space surrounded by a nucleus.
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The Planetary model's theory claimed electrons travel in orbits, circling the nucleus.
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Bohr proposed a theory for the hydrogen atom, that some physical quantities only take discrete values.
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He published a paper in which he concluded that the atomic number is the number of positive charged in the atoms nucleus.
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Schrodinger claimed the behavior of an electron within its atom can be explained by treating them mathematically as a matter of waves.
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This model is based on quantum theory, claiming matter has wave-like properties.
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Heisenberg discovered the theory that a particle's position and momentum can't exactly be known.
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Chadwick discovered the neutron and that it weighs 0.1% more than a proton.