Gabby Dunning: Famous Dead Guy Timeline

  • 101

    Democritus - 429 BC

    First person to think of the atom.
    Though atom was a solid sphere.
  • 102

    Aristotle - 400 BC

    Proposed everything was made from fire, air, water, and earth instead of atoms.
  • Sir Issac Newton

    Believed that there was little pieces of mass that were "swimming' everywhere.
  • John Dalton

    1. all matter is comosed of atoms (True)
    2. atoms cannot be made or destroyed (False)
    3. all atoms of same element are identical (False)
    4. different elements have different types of atoms (True)
    5. chemical reactions occur when atoms are rearranged (True)
    6. compounds are found from atoms of different elements (True)
  • Henri Becuerel

    He helped discover radioactivity.
  • Joseph John Thomson

    Proved the exsistence of negatively charged particles, later called electrons.
  • Robert Andrews Millikan

    He measured the charge of a single electron and mass.
  • Ernest Rutherford

    An atom has a central postive nucleus surronded by negative orbiting electrons. Credited with nucleus and proton.
  • Neils Bohr

    Depicted atom as small, postively charged nucleus surronded by electrons. Electrons travel in circular orbit.
  • Francis Aston

    Discovered isotopes of non-radioactive elements
  • Erwin Schrodinger

    atom consists of nucleus and clouds. Discovered formula that calculated the odds of where an electron might be. Proved Bohr Model incorrect
  • James Chadwick

    Discovered neutron.