History of the Atom

  • Period: to

    Dalton's Atomic Theory

    His theory consisted of; all elements are composed of atoms, atoms of the same element are the same, and atoms of different elements are different from the atoms of the different element, atoms can be physically mixed together or chemically combinded to form compounds, Chemical reactonsw occur when atoms are separated, joined, or rearranged. Atoms of one element can not be changed into atoms of another element.
  • Dalton's Model

    Dalton imagines atoms are small, indestructible, structureless particles
  • J.J. Thompson

    J.J. Thompson
    British scientist, J.J. Thompson, discovered the electron. HE imagines them embeded in a positive sphere.
  • Curie's work on radioactivity

    Curie's work on radioactivity
    She, her husband, and an associate were able to show that rays emitted by uranium atoms caused the fogging of the plates in an experiment. She called the process radioactivity.
  • Rutherford's Atomic Model

    Rutherford's Atomic Model
    He propsed almost all the mass is concentrated in the nucleus where the positive charge is. The Nucles is tiny central coreof an atom.
  • Rutherford's Gold Foil Experiment

    Rutherford's Gold Foil Experiment
    Rutherford experiment proves the existence of nuclei in atoms by using a narrow beam of alpha particles directed at a thin sheet of gold foil. The beam should have gone staright through the foil but some beams were deflected at large angles proving there are neclei in atoms deflecting the beams.
  • Niels Bohr

    Niels Bohr
    In his model, the electron is a particle with a circular orbit at a fixed destance from the nucleus.
  • Quantity of Charge Experiment, Robert A. Millikan

    Using a charge-to-mass ration of an electron measured by Thomson, Millikan calculated the mass of the electron.
  • Erwin Schrodinger

    He came up with the electron cloud model where the nucleus contains protons and nuetrons.
  • James Chadwick

    Chadwick confirms the existance of nuetrons, which have no charge.