Atomic Timeline

  • John Dalton

    John Dalton
    John proposed an atomic theory that all matter is made up of tiny particles called atoms.John believed that all atoms are indivisible and indestructible building blocks of elements and matter.
  • JJ Thomson

    JJ Thomson
    He demonstrated the existence of electrons using cathode rays. Using them he showed that they have a negative charge.
  • Marie Curie

    Marie Curie
    She discovered two new elements, radium and polonium.
  • Ernest Rutherford

    Ernest Rutherford
    He theorized that atoms have their charge concentrated in a tiny nucleus, and made the Rutherford model of the atom.
  • Niels Bhor

    Niels Bhor
    He gave us the model that we currently use. The model can be summarized by 4 things... But due to lack of space I can not put in the timeline but here is the link.http://www.abcte.org/files/previews/chemistry/s1_p6.html
  • Wolfgang Pauli

    Wolfgang Pauli
    He discovered the Pauli exclusion principle, which states that in an atom no two electrons can occupy the same quantum state simultaneously.
  • James Chadwick

    James Chadwick
    Discovered the neutron. Also placed most of the mass in the nucleus.
  • Lise Meitner

    Lise Meitner
    She gave the first theoretical explanation of the fission process. She was also overlooked when her partner Otto Hahn was given a Nobel Prize
  • Vera Rubin

    Vera Rubin
    Vera Rubin and Kent Ford of the Carnegie Institution of Washington stared, confused, at the punch-card readouts from their observations of the Andromeda Galaxy. The vast spiral seemed to be rotating all wrong. The stuff at the edges was moving just as fast as the stuff near the center, apparently violating Newton’s Laws of Motion. While the explanation for that strange behavior didn’t become clear to Rubin. Two years later, these printouts represented the first direct evidence of dark matter.
  • Sheldon Cooper

    Sheldon Cooper
    Sheldon (working as a waiter) dropped plates on the ground. This made him rethink his problem that he has been working on for the whole episode (The Einstein Approximation). He realizes that the electron moves through the graphene in waves.