The Atom

  • 550


    Everything made of building blocks. *550 BC
  • Period: 550 to

    The Atom

  • Sep 18, 600


    Everything is made of atoms. *400 BC
  • Sep 18, 650


    No one argued, all matter was fire, water, earth, air. *350 BC
  • Dalton

    Dalton's Atomic Theory
    1) All elements composed of indivisible atoms
    2) Atoms of the same element are the same. Atoms of different elements are different.
    3) Atoms make compounds.
    4) Atoms are rearranged in chemical reactions. Not created. Not destroyed. Not changed
  • Dmitri Mendeleev

    First periodic table, sorted by weights, left gaps. Elements filled in the gaps later!
  • J.J. Thomson

    Discovered the electron existence, but no details "cathode ray tube"
  • Millikan

    Found charge of electron (1/2000 of atom), mass of atom
  • Ernest Rutherford

    Positive (protons) nucleus with electrons around. The nucleus was very tiny and very dense.
  • Gold Foil Experiment

    Shot alpha particles at golden foil. They should habe gone straight through, but some bounced off showing there was a nucleus, and the rest was empty space.
  • Niels Bohr

    Electrons orbitted in rings (energy levels), could jump from orbit to emit energy
  • Chadwick

    Discovered neutron (masses weren't making sense)
  • Manhattan Project

    Nuclear research, created atomic bomb for WWII, separated the atom.
  • Cloud Model

    Shroedinger- electrons are not necessarily
  • Sheldon