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Democritus is born. He lives on to create the atomic theory and make the first discoveries of atoms
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Dalton comes up with a five part atomic theory.
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He published his law of octaves. Which states that “any given element will exhibit analogues behavior to the eighth element following it in the table“. Elements were arranged in 7 octaves like the musical octaves
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He aranged the elements that were known at the time in order of relative atomic mass.
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Crookes invented the Crookes Tube and used it to discover cathode rays that had the following properties: travel in straight lines from the cathode; impart a negative charge to objects they strike; are deflected by electric fields and magnets to suggest a negative charge
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JJ Thomspn discovered the subatomic particle called the electron. He did this by using his famous plum pudding model and Crookes Tube.
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Rutherford came to the conclusion that the nucleus had a posotive charge, was very dense, and was also very small. He also made the discovery that electrons are located outside of the nucleus.
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Bohr created a explanation of atomic structure that underlied regularities of te periodic table of elements. The atomic model that he made was composed of sucessive orbital shells of electrons.
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Using alpha particles he discovered a neutral atomic particle with a mass close to a proton. This was the neutron.
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Aristotle stated his theory which was that there were only four elements. The four elements were earth,air,fire and water.
