Histroy Of The Atomic Theory Timeline

  • John Dalton

    John Dalton
    John Dalton stated a theory that the atoms the atoms of different elements can be distinguished by the weight difference. This bought up many basic ideas and using his theory, he thought up that the various laws of chemical combination which were in existence at that time. Despite many errors from John Dalton, he provided a logical explanation of different types of concepts, and opened up new fields of examination
  • Marie Curie

    Marie Curie
    Marie Curie discovered uranium rays. She learnt that some of the mysterious 'rays' emanating from radioactive substances were not rays at all, but tiny particles.
  • Joseph John Thomson

    Joseph John Thomson
    In J.J Thomson discovered the electron in a series of experiments designed to study the nature of electric discharge in a high vaccuum cathode-ray tube. This was being investigated by many scientists at the time. He also in 1904 suggested a model of the atom as a sphere of positive matter, which makes electrons be positioned by electrostatic forces.
  • Ernest Rutherford

    Ernest Rutherford
    In the early 1900's Earnest Rutherford tried out the Geiger-Marsden experimen. It was an attempt to examine the structure of the atom. He had suprising results, the experiment demoonstrated the existence of the atomic nucleus. It became a big part of the Ritherford model of the atom.
  • Henry Moseley

    Henry Moseley
    Made the X-ray spectra to study atomic structure. Henry Moseley showed that the ordering of wavelengths to do with x-ray emissions was a different ordering of the elements by atomic number. He also showed that the periodicity was a function of an atomic number, other than atomic mass.
  • Neils Bohr

    Neils Bohr
    Neils Bohr applied Rutherfords atomic structure to assume that electrons travel in stationary orbits, which is defined by their angular force. Leading to the calculation of possible energy levels, for the orbits and that the emission of light occurs when an electron moved into a lower energy orbit.
  • James Chadwick

    James Chadwick
    James Chadwick discovered the neutron, he did this by using evidence collected by Irene Joliot-Curie, who discovered beryllium bombarded with positively charged alpha particles a beam with high penetrating power was created. He also discovered that this beam was not deflected by either electric or magnetic fields, meaning it contained neutral particles- neutrons. Neutrons were found to have same mass as protons which accounted for more of the mass of the atom and allowed the masses to match.
  • Francis Aston

    Francis Aston
    Francis Aston invented the mass spectograph. It is used to seperate eletrically charged particled according to their masses. Franis Aston was the first person to observe isotopes and observed that there is three kinds of different hydrogen atoms. Francis Astons own work, led Rutherford to predict the existence of the neutron.
  • Erwin Schrodinger

    Erwin Schrodinger
    Erwin Schrodinger combined the equations for the behaviour waves with the de Broglie equation to make a mathematical model, then used for the distribution of electrons in an atom. The Schrodinger model presumes that the electron is a wave and tries to describe the regions in space, or orbitals, where electrons are most likely to be found.
  • Murray Gell-Mann

    Murray Gell-Mann
    Murray showed scientists what makes up protons and neutrons, quarks. This discovery of the quarks made quite an impact. Scientists now know the building blocks of what made up the universe, and can use that knowledge to deeper understand the beginning of time.