Atomic theory

  • John Dalton

    John Dalton
    Dalton's theory was based on that the atoms of different elements could be distinguished by differences in their weights.
  • John Newlands

    John Newlands
    John Newlands divided the than discovered 56 elements into 11 groups, based on characteristics.
  • Dimitri Mendeleev

    Dimitri Mendeleev
    Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements, and left spaces open in his periodic table for them.
  • Bequerel

    Antoine Bequerel first discovered radioactivity.
  • William Ramsay

    William Ramsay
    William Ramsay and Rayleigh discovered the noble gases, which were added to the periodic table as group 0.
  • JJ Thompson

    JJ Thompson
    Thomson interpreted the deflection of the rays by electrically charged plates and magnets as evidence of "bodies much smaller than atoms" that he calculated as having a very large value for the charge-to-mass ratio
  • Earnest Rutherford

    Earnest Rutherford
    Earnest Rutherfords theory was describing the atom as having a central positive nucleus surrounded by negative orbiting electrons.
  • Neils Bohr

    Neils Bohr
    Neil described the way atoms emit radiation by suggesting that when an electron jumps from an outer orbit to an inner one
  • James Chadwick

    James Chadwick
    James Chadwick first discovered neutrons, and isotopes were identified. This was the complete basis for the periodic table