• 500


    -500-400 BC
    -Aristotle says that Matter is created by four different elements. The elements being Earth, Fire, Water, and Air.
  • 500


    -500-400 BC
    -Democritus states that Matter is created by invisible particles called "atoms."
  • Period: 500 to

    History of the Atom

  • John Dalton

    -John Dalto is called "The Father of Atomic Theory"
    states that :
    1. atoms are small hard spheres.
    2.atoms are invisible.
    3.atoms of the same element are the same.
    4.atoms of different elements are different.
    5.atoms combine in small whole number ratios.
  • J.J Thompson

    J.J Thompson
    -Discovered the electron Cathode Ray Tube. Used the "Plum Pudding" example.
  • Ernest Rutherford

    Ernest Rutherford
    -Gold Foil Expirament. Discovered the Nucleus.
    -Nucleus:very small, very dense.
  • Robert Millikan

    discovered the charge and mass of an electron.
  • Niels Bohr

    Niels Bohr
    Planetary Model: electrons orbit the nucleus just like planets orbit the sun.
  • James Chadwick

    James Chadwick
    -discovered the neutron.