Timeline of Atoms - Cameron and Amy

Timeline created by CWylie
  • 400

    Democritis' Atomic Theory

    Democritis' Atomic Theory
    -Atoms make up everything
    -Atoms are indivisible and indestructable
    -No scientific process
    -Challenged by many other Greek philosophers
  • Dalton's Atomic Theory

    Dalton's Atomic Theory
    -Published 1802
    -All elements are composed of atoms
    -All atoms of the same element are alike and differ from all other atoms
    -Atoms can chemically combine or mix together into new compounds
    -When atoms join, seperate, or rearrange, a chemical reaction is caused
    -An atom cannot become anything else
  • Dalton's Model

    Dalton's Model
    Dalton believed that atoms were tiny, solid spheres with no smaller parts.
  • Thomson's Model

    Thomson's Model
    Thomson believed that there must be electrons scattered randomly on the surface of a tiny, solid sphere.
  • Marie Curie

    Marie Curie
    -Discovered and named radioactivity
    -Used mostly radium
    -Died of aplastic anemia, a bone condition caused by overexposure to radiation. The effects of radiation were not known at the time
    -First woman to be recognized by the Nobel Prize of Chemisty, and also the first person to recieve two Nobel Prizes
  • Nagaoka's Model

    Nagaoka's Model
    Nagaoka believed that an atom has a central nucleus.
  • JJ Thompson's Electron Theory

    JJ Thompson's Electron Theory
    -Formulated and proved the concept of electrons
    -Proved electrons to be a fundamental particle within atoms
  • Milikan's Oil Drop Experiment

    Milikan's Oil Drop Experiment
    -Used oil to prove the 'elementary electric charge,' the electric charge of an electron
  • Rutherford's Atomic Model

    Rutherford's Atomic Model
    -Used gold foil to prove that atoms are mostly empty space with a dense nucleus (model known as the Nuclear Atom)
    -Neutrons are distributed within the nucleus
    -Electrons revolve around the nucleus and fill the majority of the volume of the atom
  • Rutherford's Model

    Rutherford's Model
    Rutherford believed that the nucleus of an atom must be dense and positively charged. He also believed that electrons orbit this central nucleus.
  • Bohr's Model

    Bohr's Model
    Bohr believed that electrons orbit the nucleus at fixed distances.
  • de Broglie's Proposal

    de Broglie's Proposal
    de Broglie believed that electrons (and some other particles) had similar properties of waves.
  • Schrodinger's Proposal

    Schrodinger's Proposal
    Schrodinger believed that electrons are in fixed positions around a nucleus, leading to the Electron Cloud model.
  • Chadwick's Discovery

    Chadwick's Discovery
    Chadwick proved that there are neutral neutrons in a nucleus.