The Atomic Timeline

  • Democritus
    400 BCE

    Democritus

    He thought that atoms were very tiny, and were unable to be cut open. He also thought that the shape of the atom was the shape of the object that is made. For example, a water atom would be round, and then the atom for fire would have sharp edges on it.
  • John Dalton

    John Dalton

    He thought that the atom was a solid sphere that you couldn't divide that you no one could destroy or remake again
  • J.J. Thomson

    J.J. Thomson

    Discovered that the atom had positively and negatively charged electrons on it, that were scattered around the outside randomly
  • Max Planck

    Max Planck

    He discovered the energy that was emitted in hot water
  • Ernest Rutherford

    Ernest Rutherford

    Found that there were units in the atom that could be divided. He also found that these divisible units that were positive were located in the center of the atom, and anything that was negatively charged was orbiting around the outside of the atom
  • Robert Millikan

    Robert Millikan

    He discovered the fundamental charge of a single electron, which he discovered by doing experiments with water droplets.
  • Niels Bohr

    Niels Bohr

    He discovered that electrons in an atom are similar to the planets in orbit, in the fact that they can only orbit in a certain circle, and cannot stray from their circle
  • Erwin Schrodinger

    Erwin Schrodinger

    A probability to find electrons within a space surrounding the nucleus. The cloud is denser where the probability of finding an electron is high. The cloud is less dense where the probability of finding an electron is low.
  • Werner Heisnberg

    Werner Heisnberg

    When he was twenty-three, he published his uncertainty principle, and was later rewarded a Nobel prize for his subsequent researc h
  • Dmitiri Mendeleev

    Dmitiri Mendeleev

    He is the one who made the very first periodic table. This table was organized by the elements atomic number, which is according to the atoms that make up the element.
  • Eugene Goldstein

    Eugene Goldstein

    With the experiments that he did, Goldstein discovered the proton on the atom.
  • James Chadwick

    James Chadwick

    He discovered that the atom also has a nucleus that is located in the center of the atom, with the protons. This nucleus can be positively or negatively charged, and also contributes to the atomic weight of the object