Chariti's Atomic Theory Timeline

By cnettles4620
  • 370 BCE

    Democritus

    Provided a more detailed and systematic view of the physical world.
  • 332 BCE

    Aristotle

    Believed materials on Earth were made of Earth, Fire, Water, and Air.

  • Antoine Lavoisier

    Mass is conserved in a chemical reaction, but the oxygen and hydrogen atoms stay the same before and after.

  • Joseph Louis Proust

    Published his law of definite proportions, which states that a compound is composed of exact proportions of elements by mass regardless of how it was created.

  • John Dalton

    Introduced a theory that proposed that elements differed due to the mass of their atoms.

  • Michael Faraday

    Discovered that a magnetic field influenced polarized light.

  • Henri Becquerel

    Discovered the existence of radioactivity.

  • J.J. Thomson

    Discovered the electrons in atoms.

  • Marie & Pierre Curie

    Deduced that radioactivity does not depend on how atoms are arranged into molecules, but rather that it originates within the atoms themselves.

  • Albert Einstein

    Calculated how the movement of molecules in a liquid can cause the Brownian movement.

  • Robert Millikan

    Helped to quantify the charge of an electron.

  • Ernest Rutherford

    Demonstrated the atom has a tiny, heavy core.

  • Niels Bohr

    Proposed a theory for the hydrogen atom based on quantum theory that energy is transferred only in certain well defined quantities.

  • Max Planck

    Originator of the quantum theory of energy.

  • James Chadwick

    Discovered the Neutrons in atoms.