J Wilder Famous Dead Guys Timeline

  • 101

    Democritus - 429 BC

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

    Aristotle - 400 BC

    Determined that all things were made up of fire, water, earth, and air.
  • Sir Isaac Newton

    Thought everything was made up of atoms.
  • John Dalton

    True: All matter=atoms
    False: Atoms=no destroy
    False: Atoms of same element=identical
    True: Diff. elements= different atoms
    True: Chem. reaction=atoms rearranged
    True: compounds=atoms of different elements
  • Henri Becquerel

    Helped discovery radioactivity
  • Joseph John Thomson

    Found electrons
    Thought atoms looked like plum pudding
  • Robert Milikan

    Measured the charge and mass of electron
  • Ernest Rutherford

    Central position- nucleus surrounded by negative orbiting electrons.
  • Niels Bohr

    Depicted atoms as small, positively charged nucleus surrounded by electrons- moved in circular motion
  • Francis Aston

    Discovered isotopes of non-radioactive elements
  • Erwin Schrodinger

    Discovered formula that calculated the odds of where an electron might be.
    Proved Bohr model incorrect
  • James Chadwick

    Discovered the neutron