Atomic Theory

By 2015lehmanhi
  • 400

    Democritus

    (400 BC) First suggested the existence of atoms

  • Newton

    wanted to explain what was known about light's behavior assuming light consists of particles

  • Lavoisier

    First to use truely quantitative research. Observations led to the law of conservation of mass

  • Proust

    Observeed that the composition of water is always 11% hydrogen and 89% oxygen. Proposed the law of definite proportions.

  • Dalton

    Transformed the idea and formed Dalton's atomic theory

  • Dobereiner

    published classification system

  • Mendeleev

    formulated the periodic table of elements.

  • Crooke

    Created the cathode ray tube and found that there was charged particles that flowed through the tube when electricity was passed through the tube.

  • Eugen Goldstein

    Observed cathode ray and saw some particles were going the opposite way of the cathode rays. He called those particles protons.

  • Bequerell

    studied the affect of x-rays on photographic film. He discovered some chemicals spontaneously decompose and give off very pentrating rays.

  • JJ Thomson

    Discovered the electron when expiramenting with a cathode ray. Created the plum pudding model

  • Curie

    discovered the radioactive elements polonium and radium

  • Planck

    Tried describing why metals start blackthen red, yellow, white as temperature increases

  • Einstein

    Used quantum theory to explain photoelectric effect. His theory was that light behaves as a stream of particles and explains the photo electric effect

  • Millikan

    Carried out JJ's expiraments; oil drop expirament

  • Ernest Rutherford

    Found that atom has a small dense positively charged nucleus. He did the gold foil expirament

  • Bohr

    Proposed that an atom absorbs/emits light and that the electron is found in a specific path around the nucleus

  • Moseley

    Using x-ray tubes he determined the charges on the nuclei of most atoms

  • DeBrogile

    Asked can particles behave as matter?

  • Schrodinger

    Made the quantum mechanical model. Electrons don't follow a specific path but is found in a cloud around the nucleus.

  • Heisenberg

    uncertanty principle. Stated that it is impossible to know both velocity and position of a patricle at the same time

  • James Chadwick

    Discovered the neutron