History of the Atom

  • 460


    Democritus thought breaking a piece of matter in half had to end sometime and called those particles atoms.
  • John Dalton

    John Dalton
    Dalton did experiements with different chemicals proving matter consisted of atoms and came up with the solid sphere model.
  • J.J. Thomson

    J.J. Thomson
    Thomson discovered the electron and presented a model for the atom structure (Plum Pudding Model) It shows the atom is positvely charged (pudding) and the negitive electrons are randomly throughout (plumbs)
  • Albert Einstein

    Albert Einstein
    Einstein published the famous equation E=mc^2 proving atoms existed.
  • Robert Millikn

    Robert Millikn
    Millikah's oil drop expierement determined the unit charge of electrons.
  • Ernest Rutherford

    Ernest Rutherford
    Rutherford established the nucleus is the center and positive it is made of protons and neutrons, negative electrons orbit around the atom called the nuclear model.
  • Niels Bohr

    Niels Bohr
    Bohr had the theory electrons do not spiral into the nucleus and he came up with the first model of an atom called the planetary model.
  • Neils Bohr

    Neils Bohr
    Bohr and Sommerfeld expanded the origional model, it showed not only do electrons travel in certain orbits, but they have different shapes and could tilt within a magnetic field.
  • Wolfgang Pauli

    Wolfgang Pauli
    Pauli predicted an electron should spin either direction while it orbits around the nucleus turning that into his exclusion principle.
  • Louis de Brogile

    Louis de Brogile
    De Brogile showed what matter waves would be like if they existed. He added onto Bohr's model of the atom and in 1929 he received the Nobel Prize.
  • Werner Heisenberg

    Werner Heisenberg
    Heisenburger had a theory called metric mechanics which explained the behavior of atoms based on math quantities (matrices)
  • Erwin Schrödinger

    Erwin Schrödinger
    Schrödinger saw electrons as clouds and made a symbol/equation based on waves.
  • James Chadwick

    James Chadwick
    Chadwick discovered the neutron and figured out it measures slightly heavier than a proton.