Atomic Theory Timeline Project

  • Democritus
    400 BCE

    Democritus

    -Atoms are "uncuttable"
    -Atoms are Small, Hard particles
    -Atoms constantly move
  • Democritus Model
    400 BCE

    Democritus Model

  • John Dalton

    John Dalton

    -All substances are made up of atoms.
    -Atoms of different elements are different.
    -Atoms of the same element are exactly the same.
    -Elements combine in specific proportions.
    - He conducted experiments in combining elements.
  • John Dalton Model

    John Dalton Model

  • JJ Thomson

    JJ Thomson

    -He conducted the cathode-ray experiment
    -His theory of the atomic structure lead to the "plum-pudding" model.
    -There are small negatively charged particles inside an atom.
  • JJ Thomson Model (Plum Pudding)

    JJ Thomson Model (Plum Pudding)

  • Ernest Rutherford Model

    Ernest Rutherford Model

  • Ernest Rutherford

    Ernest Rutherford

    -Atoms contain mostly empty space
    -He conducted the gold foil experiment
    -Most of an Atom's mass is in the nucleus
    -There is a small, dense, positively charged nucleus
  • Niels Bohr

    Niels Bohr

    -Electrons jump between levels from path to path
    -Electrons move in empty space
    -Electrons travel in definite paths.
  • Neils Bohr Model

    Neils Bohr Model

  • Erwin Schrodinger and Werner Heisenberg

    Erwin Schrodinger and Werner Heisenberg

    -Electron paths can not be predicted.
    -Electrons are found in electron clouds, not paths.
    -Electron paths cannot be predicted.
  • Erwin Schrodinger and Wener Heisenberg Model

    Erwin Schrodinger and Wener Heisenberg Model