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Evolution of Atoms

By LehDolphinLord
  • 470 BCE

    Democritus

    Democritus
    Democritus inherited studying the atomic theory from his teacher, Leucippus. He figured atoms were miniscule quantities of matter. He also supposed the atoms, which are originally similar, to be impenetrable and have a density proportionate to their volume.

  • John Dalton

    John Dalton
    John Dalton got into studying the Atomic Theory through meteorology. After years of looking into it, he assumed that air is not a chemical solvent, instead it is a mechanical system. Dalton also claimed that the forces of repulsion thought to cause pressure acted only between atoms of the same kind within another gas. He published his thoery around 1803

  • John Thomson

    John Thomson
    John Thomson proposed the "Plum-Pudding" Atomic model in 1904.The model suggested that the atom was charged by smaller positive and negative charged material.

  • Ernest Rutherford

    Ernest Rutherford
    Enerst Rutherford is best known for his "gold foil" experiment. The experiment was conducted using an extremely thin strip of golden tin foil and alpha particles as the bullets.This concluded in the discovery of the group of particles, the nucleus, in the middle of the atom. He published his discovery in 1911

  • Niels Bhor

    Niels Bhor
    Niels Bhor used the teachings from J.J Thomson and the discovery of Rutherford to propose a theory for the hydrogen atom. The theory was based on the quantum theory that energy is transferred only in certain well defined quantities. His discovery of the electron and radiation led to more, different constructions of the atomic model. He published his theory in 1913

  • Erwin Schrodinger

    Erwin Schrodinger
    Erwin Schrodinger developed the "cloud model" of the atom. The model suggested that the nucleus was surrounded by a dense cloud/barrier of electrons. Experimented in 1926

  • James Chadwick

    James Chadwick
    James Chadwick, in 1932, performed an experiment by bombarding beryllium atoms with alpha particles. This produced a radiation that wasn't known. He then assumed that this was composed of the negative charge of the electron and the mass of the protons. With it being neutral, the new name of the "unknown radiation" was neutron.