Atomic Theory Timeline

  • Democritus 400BC
    400

    Democritus 400BC

    In 400 BC he was the first to propose the theory of atoms, calling them atomos.
  • Anoine Lavoisier

    Anoine Lavoisier

    In 1778 discovered the Law of Conservation.
  • John Dalton

    John Dalton

    Can be said as the father of the atomic theory. He came up with it in 1803 and purposed it.He thought that only like atoms in a mixture of gases repel one another, and unlike atoms appear to react indifferently to each other. He believed that different elements vary in size and mass, this was his main feature to his atomic theory.Came up with the atomic theory saying that everything is made up of atoms whether it be a gas, liquid, or a solid.
  • J.J. Thomson

    J.J. Thomson

    Created the Cathode ray and calculated charge to mass ratio of electrons.
  • Marie Curie

    Marie Curie

    She discovered radioactivity and the relationship radioactivity and the origin of the atoms.
  • Albert Einstein

    Albert Einstein

    Albert Einstein established the equation E=mc^2, Brownian Motion, and Photoelectric effect. Also came up the Theory of Relativity.
  • Ernest Rutherford

    Ernest Rutherford

    Conducted the gold foil experiment identifying properties of alpha and beta particles and discovering the nucleus.
  • Robert Millikan

    Robert Millikan

    Found the charge of a single electron and confirmed Thompson’s hypothesis.

    Accurately determined the charge of an electron by the means of The falling-drop method. Also that this quantity was constant for all electrons.
  • Niels Bohr

    Niels Bohr

    Niels Bohr atomic model not only explained the structure of the Rydberg formula and its reasoning but also gave a reason for its unclear result in terms of fundamental physical constant.
  • Werner Heisenbery

    Werner Heisenbery

    Came up with how to count units in an atom.He also calculated the behavior of electrons and other subatomic particles.
  • Erwin Schrodinger

    Erwin Schrodinger

    Calculated the likelihood of finding an electron in any given location around an atom. Described elctron orbit clouds.
  • Louis De Broglie

    Louis De Broglie

    His work allowed others to build off it to further investigate atoms. His work was the basis of the wave mechanics theory.
  • James Chadwick

    James Chadwick

    Discovered neutrons and their properties.
  • Max Planck

    Max Planck

    His quantum theory accounted for many problems between some phenomena and classical theory.He discovered that energy emitted by a resonator could only take on discrete values or quanta. He discovered that energy emitted by a resonator could only take on discrete values or quanta. He discovered this by experimental observations on wavelengths distribution of the energy put out as temperature. Also had his Planck Constant h=6.626 x 10-34 power Ja