Atomic Model Timeline

Timeline created by kela
  • John Dalton

    John Dalton
    John Dalton was an English chemist who proposed the Atomic Theory, which stated that all matter was composed of small particles called atoms. He found the atomic weight and chemical symbols. He invented this theory by testing different gases and used evaporation to find out what the gases had on that mixture all together.
  • J.J. Thomson

    J.J. Thomson
    Thomas was a british scientist. He found electrons and subatomic particles when he was working with cathode ray tubes. He developed the plum-pudding model and describes the atom as a positive sphere with small electrons inside.
  • Plum-pudding Model

    Plum-pudding Model
    This model was proposed before the discovery of the atomic nucleus. In this model, the atom was a sphere of positive electricity, surrounded with negatvie particles
  • Hantaro Nagaoka

    Hantaro Nagaoka
    Nagaoka developed a planetary model of the atom. His model was based around the explanation of the stability of the Saturn rings. He proposed a model in which a positively charged center is surrounded by revolving electrons.
  • Earnest Rutherford

    Earnest Rutherford
    Rutherford proposed that the atom is mostly empty space. He theorized that atoms have their positive charge concentrated in a small nucleus, which deflected some of the alpha particles. he finds that electrons move around the nucleus.
  • Gold-Foil Experiment

    Gold-Foil Experiment
    Rutherford did the gold-foil experiment where he discovered the nucleus. he used a thin foil made of gold metal to find positive and negative charges in an atom.
  • Niels Bohr

    Niels Bohr
    Niels figured out the structure of the atom, and their radiations. He discovered that electrons travel only in certain orbits around the nucleus. He inferred that when an electron moves from an outer orbit to an inner orbit, it emmits a quantum of energy in the form of light.
  • Louis de Broglie

    Louis de Broglie
    Louis was a French physicist, who suggested that the wave and particle interpretations of light and matter were the same behavior. He found out that particles can behave like waves, and radiation waves can behave like particles.
  • Electron Cloud

    Electron Cloud
    This was discovered by Erwin Schrodinger and Werner Heisenberg. According to their theory, an atom consists of a dense nucleus . The atoms protons and neutrons are surrounded by electrons, but they have different energy levels and charges.
  • Erwin Schrodinger

    Erwin Schrodinger
    Erwin generated a mathmatical model for the distribution of electrons in an atom. He worked out math equations and used statistics to find the wave and quantum mechanics.
  • James Chadwick

    James Chadwick
    James discoverd the existence of a neutron. He found this out because their was no charge in the neutron after looking at alpha waves.