Atom 68866 640

Atomic Theory Timeline

By chaneyscott
  • 442 BCE

    Democritus

    Democritus came up with the idea that matter was made up of invisible particles called atoms.
  • 350 BCE

    Aristotle

    Aristotle believed that all matter wasn't made up of atoms, but of the four elements, earth, wind, water, and fire.

  • Evanglista Torricelli

    Stated that atoms were specific to the thing they came from.

  • Antoine Lavoisier

    Stated that matter could not be created or destroyed.

  • John Dalton

    Proposed a new atomic theory using spherical solid.

  • J.J. Thomson

    Suggested model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces.

  • Ernest Rutherford

    Stated that the atom has a tiny, heated nucleus using the gold foil experiment.

  • Robert Millikan

    Discovered how to measure the charge of an electron.

  • Niehls Bohr

    Discovered that electrons travel in separate orbits around the nucleus.

  • Werner Heisenburg

    Found out that electrons don't travel in neat orbits, and included quantum physics in the atomic theory.

  • Erwin Schrodinger

    Used mathematical equations to describe the likelihood of finding an electron in a certain position.

  • James Chadwick

    Discovered neutrons in the atom.