220px stylised lithium atom

Atomic model/Theory Timeline Project

  • Leucippus
    430

    Leucippus

    B.C.E. He was the first person to develop the theory of atomism, "the idea that everything is composed entirely of various imperishable, indivisible elements called atoms"
  • Democritus
    460

    Democritus

    B.C.E. Expanded on Leucippus' theory of the atom. His discoveries are still used today.
  • Dalton

    Dalton

    Dalton found the atomic theory of matter, adding to it the idea that different elements had different characteristic atomic weights. Also in his work is the earliest depictions of the molecular structure, in which the atoms in a molecule are arranged in space in a specific fashion.
  • Revolutionary War begins

    Revolutionary War begins

  • U.S. Civil War begins

    U.S. Civil War begins

  • Thomson

    Thomson

    Discovered the electron, and theorized the design of an atom; the protons in the center with the electrons flying around a great distance from them.
  • Planck

    Planck

    He originated quantum theory.
  • Period: to

    Scientific Timeline

  • Millikan

    Millikan

    He determined the unit charge of an electron. This allowed for the calculation of electrons, and positively charged atoms.
  • Rutherford

    Rutherford

    Described the atom as having orbiting electrons around a cluster of protons. He said that most of the mass is in the conter, and the rest of the atom is mostly empty space.
  • Bohr

    Bohr

    Applied quantum theory to previous theorys about the setup of am atom. His assiumptions led to calculations of energy levels in electron orbits.
  • Schrodinger

    Schrodinger

    Determined the wave/particle duality of nature.
  • Louis de Broglie

    Louis de Broglie

    Broglie discovered the wave nature of electrons.
  • Heisenberg

    Heisenberg

    Came up with the "Heisenberg Uncertainty principle," which states that no experiment canmeasure the momentum and the position of a particle at the same time.
  • Chadwick

    Chadwick

    Proved the existence of the neutron.
  • Hawaii became the 50th state

    Hawaii became the 50th state

  • Korean War begins

    Korean War begins

  • Chernobyl

    Chernobyl

  • Empedocles

    Empedocles

    B.C.E. Discovered air as a seperate substance.
  • Plato

    Plato

    B.C.E. Plato said that the atoms that make up everything are made of right triengles.
  • Aristotle

    Aristotle

    B.C.E. Theorized that all things were made up of a potential, their matter, and their reality (or form).