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The History of the Atom

  • Democritus
    460

    Democritus

    460 BC-370 BC
    Believed matter was made up of atoms which he said where physically indivisble, has space between them but always stayed in motion.
  • Antoine LAvoisier

    Antoine LAvoisier

    1743-1794
    He proved the law of conservation
  • Joseph Proust

    Joseph Proust

    1754-1826
    He was known for proving that every pure compont consists of elements in a definite proportion
  • John Dalton

    John Dalton

    1766-1844
    saId that chemical reactions can be explained by the union and separation of atoms, and that these atoms have characteristic properties. have five assuptions to his theory
  • Heneri Becquerel

    Heneri Becquerel

    1852-1908
    while doing an experiment of the exposure of a uranium bearing ccrytal to sunlight; he discovered radioactivity.
  • Masrie and Pierre Curie

    was interested in Henri becquerel experimenttts and end up finding two new radioactive elements
  • JJ Thomson

    was able to measure the rays of cathode rays at which they were deflected, and then caculated the ratio of the electrical charge tot the mass of the particles.
  • Ernest Rutherford

    Ernest Rutherford

    found that atoms are mainly made up of empty space. became known as the father of nuclear physics
  • robert millikan

    robert millikan

    measured the charge of an electron
  • James Chadwick

    He discovered the neutron