Development of Atomic Theory

Timeline created by eliza_wittmann
  • 440

    Democratus

    Democratus
    Greek philosopher who said that everything is made up of atoms.
  • John Dalton

    John Dalton
    Was English and came up with the first real atomic theory, which said that "All matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties Compounds are formed by a combination of two or more different kinds of atoms. And a chemical reaction is a rearrangement of atoms.”
  • Rydberg

    Rydberg
    -Johannes Rydberg, Swedish
    -created Rydberg Constant

    -physical contact that has to do with the science of spectroscopy, specifically the atomic spectra
  • Thomson

    Thomson
    -Joseph John Thomson, English
    -explorations on the properties of cathode rays → discovered electrons
    -plum pudding model
  • Planck

    Planck
    -Max Karl Ernst Ludwig Planck, German
    -oscillator could only emit energy in a discrete quanta
    → quantum theory : nobel prize in 1918
  • Albert Einstein

    Albert Einstein
    German who created the theory of relativity. Which was the metric theory of gravitation and laid the basis for atomic studies.
  • Millikan

    Millikan
    -Robert Andrews Millikan, American
    - "falling-drop method" - accurate determination of the charge carried by an electron
    -demonstrated the atomic structure of electricity
  • Mosley

    Mosley
    -Henry Gywn Jeffreys Mosley, English Physicist
    -Mosely’s law - complete understanding of atomic number and positive and negative charges in the atom
  • Rutherford

    Rutherford
    -Ernest Rutherford, British, New Zealand
    -made a new model of the atom
    -discovered the electron cloud did not influence alpha particle scattering
    - said Thomson’s “plum pudding model was incorrect”
  • Niels Bohr

    Niels Bohr
    He was born in Denmark. Said that electrons were and clouds and could jump from cloud to cloud, and light is released when they jump.
  • Louis De Broglie

    Louis De Broglie
    French man who created the matter and wave-partial duality, which started wave mechanics. He came up with this idea after Einsteins discovery of photons, which moved on waves.
  • Pauli

    Pauli
    -Wolfgang Pauli, Austrian
    -Pauli exclusion principle -no two identical particles with half-integer spin may occupy the same quantum state at the same time
  • Friedrich Hund

    Friedrich Hund
    German who discovered that there must be electrons in each level before they double up.
  • Werner Heisenberg

    Werner Heisenberg
    German who published the Uncertainty Principal which said that the more you know about the location of a particle, the less is known about the momentum.
  • James Chadwick

    James Chadwick
    English man who discovered the neutron by smashing alpha particles into Beryllium, which released neutrons. This help explain the weight of atoms.
  • Schroedinger

    Schroedinger