Chemistry Atom Scientists: Marissa and Ashlyn

By Marissa G.
  • 465 BCE

    Democritus

    Democritus
    First to propose the idea of the atoms, claiming we are all made of atoms. Atomos = indivisible

  • John Dalton

    John Dalton
    Creator of the Atomic Theory. Billiard ball theory stated:
    1) All elements are made of indivisible (can't be separated) atoms (false)
    2) Atoms of the same element are identical (false)
    3) Atoms of different elements are different (true)
    4) Atoms combine chemically to make compounds (true)

  • JJ Thomson

    JJ Thomson
    Proposed the existence of negative electrons. Said negative electrons swam in a positively charged atom (not true)

  • Ernest Rutherford

    Ernest Rutherford
    Did the gold foil experiment which showed that there is a positively charged small nucleus in the middle of an atom, and the rest of the space is mostly empty in an atom.

  • Niels Bohr

    Niels Bohr
    Proposed the idea that electrons were in energy levels (true). That they orbited the nucleus like planets orbit the sun in his planetary model (not true).

  • Erwin Schrodinger

    Erwin Schrodinger
    Said electrons were found in clouded orbital regions. Knew where to find electrons.

  • James Chadwick

    James Chadwick
    Discovered the mass of an element's atom were not always the same. Found neutrons were neutral and in the nucleus. Isotopes = same number of protons, different neutron numbers.