Atoms

By cwidje
  • 370

    Democritus

    Thought that everything was composed of small particles called atoms. 1

  • Isaac Newton

    Used experimental methods to turn Democritus's ideas into a scientific theory.

  • John Dalton

    1. All elements are made of tiny, indivisible particles called atoms.
    2. Atoms of the same element are the identical. Atoms of different elements are different.
    3. Atoms form compounds.
    4. Atoms are never created or destroyed, only rearranged.

  • Dmitri Mendeleev

    Used atomic weight to organize the first periodic table.

  • J.J. Thompson

    Proved the existence of negative electrons via a cathode ray tube.

  • Ernest Rutherford

    Used a "gold-foil experiment" to prove that the nucleus was positive and that the electrons orbited it.

  • Max Planck

    Vibrated atoms to shwo measureable energy (quanta).

  • Niels Bohr

    Proved that electrons orbit at energy levels.

  • Albert Einstein

    Created formula for atomic power. e=mc^2

  • Robert Millikan

    Used "oildrop" experiment to prove mass of electron=1/2000 of proton. Charge of electron=-1 Charge of proton=+1

  • Erwin Schrödinger

    Electrons have erratic orbits.
    Electron cloud model.

  • James Chadwick

    Proved the existence of the neutron.