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History of the Atom

By joshhof
  • Democritus
    Sep 23, 1500

    Democritus

    Developed the idea tht everything is created from atoms at around 400 B.C. He also said that atoms are indivisble and cannot be broken down.
  • John Dalton

    John Dalton

    The solid sphere model was John's Dalton's explanation of the atom. It was a solid, indestructible sphere. It didn't include a nucleus or subatomic particles.
  • J.J. Thomson

    J.J. Thomson

    The plum pudding model, proposed by JJ Thomson, was seen as the atom before the discovery of the atomic nucleus. The model is composed of electrons surrounded by positive charge to balance the negative charges.
  • Albert Einstein

    Albert Einstein

    Einstein published papers on a new method of counting and determining the size of the atoms, and on the phenomenon of Brownian motion that proved that atoms actually exist.
  • Robert Millikan

    Robert Millikan

    Robert Millikan is credited for measuring the charge of an electron. He also accomplished the oil drop experiment, which he completed with JJ Thomson.
  • Ernest Rutherford

    Ernest Rutherford

    Rutherford published his atomic theory discribing the atom as having a central nucleus surrounded by negative orbiting electrons. He found this out by doing an experiment with his gold foil model which contained a detecting screen. Created the planetary Atom model.
  • Niels Bohr

    Niels Bohr

    Bohr proposed that electrons travel only in certain successively larger orbits. He helped develop quantum mechanics, in which electrons move from one energy level to another.
  • Louis deBroglie

    Louis deBroglie

    His theory helped explain how atoms, molecules, and protons, behave. He suggested that all matter has wave properties.
  • Werner Heisenburg

    Werner Heisenburg

    German physicist who cam up with his own priciple which states that if you measure one particle the other may not be certain.
  • Wolfgang Pauli

    Wolfgang Pauli

    Nominated for contribution through his discovery of a new law of Nature, the exclusion principle or Pauli principle. No two electrons can hold the same 2 quatam numbers.
  • Erwin Schrödinger

    Erwin Schrödinger

    Formed a model off of particle waves
  • James Chadwick

    James Chadwick

    James discovered the neutron in the atom.