Development of the Atomic theory

By noahyoussef__
  • 400 BCE

    Democritus

    Democritus was the first to identify the possibility of an atom, which would be the smallest piece of matter
    He theorized that atoms are inpenetrable and have a density proportionate to their volume
    His theory states that atoms ate internal as is motio

  • John Dalton 1808

    Dalton's experiments on gases led to his discovery that the total pressure of a mixture of gases amounted to the sum of the partial pressures that each individual gas exerted while occupying the same space. Dalton's fascination with gases gradually led him to formally assert that every form of matter (whether solid, liquid or gas) was also made up of small individual particles.

  • Sir J.J. Thomson

    In 1904 Thomson suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces. Thomson’s last important experimental program focused on determining the nature of positively charged particles. Here his techniques led to the development of the mass spectrograph.His nonmathematical atomic theory unlike early quantum theory could also be used to account for chemical bonding and molecular structure see Gilbert Newton Lewis and Irving Langmuir.

  • Lord Rutherford

    In 1895, as the first research student at the University of Cambridge’s Cavendish Laboratory in London, Rutherford identified a simpler and more commercially viable means of detecting radio waves that had been previously established by German physicist Heinrich Hertz.Chemist and physicist Ernest Rutherford were born August 30, 1871, in Spring Grove, New Zealand. Rutherford was awarded the 1908 Nobel Prize in Chemistry for his theory of atomic structure. Dubbed the “Father of the Nuclear Age,

  • Niles Bohr

    Niels Bohr became an accomplished physicist who came up with a revolutionary theory of atomic structures and radiation emission. He won the 1922 Nobel Prize in physics for his ideas and years later, after working on the Manhattan Project in the United States, called for responsible and peaceful applications of atomic energy across the world.Bohr worked with the group of scientists who were at the forefront of research on nuclear fission during the late 1930s.

  • Sir James Chadwick

    In 1935 Chadwick was appointed to a chair in physics at the University of Liverpool. In 1940 he was part of the MAUD Committee, which was to assess the feasibility of the atomic bomb. The committee concluded in 1941 that the 1940 memorandum of Otto Frisch and Rudolf Peierls was correct and that a critical mass of only about 10 kilograms 22 pounds of uranium were needed.