Scientists Contribution to the Atomic Theory

  • 470


    Democritus hypothesised that everything is comosed of atoms.
  • Antoine Lavoiser

    Published book containing well, founded concept of chemical elements and the verification of the law of conservation of matter in chemical reactions.
  • Joseph Louise Proust

    Established the law of definite proportions for chemical compounds.
  • John Dalton

    Proposed the atomic theory, said atoms are spherical and solid with masses based on a measurable properties of mass.
  • Eugene Goldstien

    Introduced name 'Cathode Rays' and began expiriments leading eventually to the discovery of the positive counter part, canal rays. Also suggested aurora is due to cathode rays from the sun.
  • J.J. Thomeson

    determined the charge to mass ration of an elction = 1.7459x108 coulombs/grams by using CRT. Also, canal rays were associated with the proton H+.
  • Marie Curie

    Insolated radium and polonium. Awarded nobel prize for phsics in 1903, and nobel prize for chemistry in 1911.
  • Robert Millikan

    Determined the mass and charge to an electron.
  • Ernest Rutherford

    Identified positively charged particles (protons) which gave atoms most of its mass, he proposed that had a small positive nucleus that was surrounded.
  • Henry Mosely

    Declared the atomic numbre was the number of protons and neutrons, thus, leading to the rearrangement of the periodic table.
  • Niels Bohr

    Developed an atomic model that had atoms built up successive or bital shells of electrons
  • Erwin Shroedinger

    Proposed wave mechanical theory of the hydrogen atom. Was awarded Nobel prize for physics with Paul Dirac.
  • Dmitri Mendeleev

    Obtained 1st alound chamber photograph of cosmic rays. These showed that the rays either wave, or produced, many changed, high energy particles.
  • James Chadwick

    Discovered a neutral atomic particle with a mass close to a proton. Thus was discovered the neutron.
  • Lise Meitner

    Discovered that when an atom splits, it makes a huge explosion with alot of radiation.