Histroy of the Atom Timeline Project

  • john dalton

    Proposed an "atomic theory" with spherical solid atoms based upon measurable properties of mass. Also he believed that all matter is made up of atoms, and that matter is impossible to destroy.
  • Dalton model

    He didnt realize that neutrons and protons existed.
  • William Crooke

    Discovered cathode rays had the following properties: travel in straight lines from the cathode; cause glass to fluoresce; impart a negative charge to objects they strike; are deflected by electric fields and magnets to suggest a negative charge; cause pinwheels in their path to spin indicating they have mass.
  • J.J Thomson

    He experimentally determined the charge of mass ratio of an electron.
  • Ernest Rutherford

    Discovered the radiation gave radiation from uranium and thorium and named them alpha and beta.
  • Thomson's Atomic Model

    He said that matter contained particles that were the same and are smaller than the atoms that matter is formed from.
  • Rutherford Model

    He proved that JJ thomson theory of atom was incorrect.contained the new features of a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and with this central volume also containing the amount of atomic mass.
  • Niels Bohr

    Developed an explanation of the structure of the periodic table of elements. His atomic model had atoms built up of sucessive orbital shells of electrons.
  • Modern Atomic Model

    Electrons are in constant motion around the nucleus, protons and neutrons jiggle within the nucleus, and quarks jiggle within the protons and neutrons.
  • Bohr's Atomic Model

    Provides that atoms as small as they are, they are positively charged nucleus sorrounded by electrons that sorround the nucleus.
  • James Chadwick

    Using alpha particles discovered a neutral atomic particle with a mass close to a proton.