Atomic Theory

Timeline created by Billsgn
  • 400

    Discovery of atom

    Atoms were first discovered by Democritus.
  • Phosphorus discovered

  • Hosphorus became public

  • Johann Dobreiner

    Johann Dobreiner grouped elements based on the elements
  • Atomic Theory is first thought up

    John Dalton comes up with the Atomic Theory
  • 47 elements discovered

    47 elements were discovered. People began to see patterens in the elements.
  • Law of traids

    The law of traids is thought up which grouped elements based on similarities of the elements.
  • X-Rays discovered

    Willhelm Roentgen discovers chemicals that glowed in a CRT. Some rays within the chemicals weren't deflected by a magnetic field, and called these rays "X-Rays".
  • First Cathode Ray tube made.

    J. Plucker invents the Cathode Ray tube, which is used for making X-rays
  • Law of Octaves

    The Law of Octaves is thought of, which again helps show similarities in elements discovered.
  • Atomic Weight

    Elements are organized by atomic weight.
  • Dimitri Mendeleev

    Development of the periodic table started by Dimitri Mendeleev.
  • Radioactiviy

    Radioactivity discovered by Antoine Bequerel
  • Henry Moseley

    Henry Moseley performed x-rays on known elements.
  • X-rays

    Henry Moseley performed x-rays on known elements.
  • Noble gas

    Group 0 was added to the periodic table, known as noble gases.
  • Electrons

    Electrons were discovered by J.J. Thomson.
  • Electron Discovered

    JJ thomson discovers the electron.He describes atoms as a ball of positive energy containing a number of electrons.
  • Beta particles

    Beta particles and electrons were discovered.
  • Radioactivity

    Radioactivity caused breakdown of atoms.
  • Nucleus

    Electrons orbit around the nucleus. Discovered by Rutherford and Hans Geiger.
  • Orbitals

    Electrons are in energy called orbitals. Radiation is released by movement
  • Protons

    Rutherford discovered protons in the nucleus.
  • Isotopes discovered

    Aston uses a spectrograph and discovers isotopes, variations in atoms where the amount of neutrons has been changed.
  • Atoms are "succesive or bital shells of electrons"

    Neils Bohr becomes the father of Quantum Theory. He propses that atoms are "succesive or bital shells of electrons" and comes up with the "Bohr Planetary Model"
  • Nucleus of atom discovered to have a positive charge

    Ernest Rutherford discovers that the nucleus of an atom has a positive charge.
  • Electron Cloud Theory introduced

    Electron Cloud Theory introduced by Erwin Schrodinger.
  • Neutrons and isotopes

    Neutrons and isotopes were discovered by James Chadwick.
  • Lanthanides and actinides

    Lanthanides and actinides were discovered by Glenn Seaborg.
  • Neutron Discovered

    James Chadwick discovered the neutron.
  • Alpha Particles made

    John Douglas Cockcroft and Ernest Thomas Sinton Walton put lithium with protons and created alpha particles.
  • Cyclotron invented.

    Ernest Lawrence invented the cyclotron then realized potential for isotopes.
  • First chain reaction from atoms releasing energy.

    First chain reaction releasing energy from atoms by Enrico Fermi.
  • First atomic bomb dropped.

    The first atomic bomb is dropped by Us soldiers onto Japan for World War II
  • 60 elements

    60 more elements were discovered.