Periodic developement assienment

  • Henning Brand

    Henning Brand
    although gold, silver, tin, copper, lead and mercury have been known since antiquity. phosphorus was the first discovery dicoververed by a scientist called hennig brand, in 1649.
  • John Dobereiner

    John Dobereiner
    Johann dobereiner noticed that the atomic weight of strontium fell midway between the weights of calcium and barium.
  • John Newlands

    John Newlands
    In 1863 an english chemist wrote a paper, which classified the 56 established elements into 11 groups based on similar physical properties.
  • Sir William Rampsay

    Sir William Rampsay
    in 1894 sir wiliam ramsay and lord rayleigh dicscovered the nobal gases, which were added to the periodic table as group 0.
  • J.J Thompson

    J.J Thompson
    English physicist jj thompson discovered the first electrons, small negatively charged particles in an atom.
  • Neils bohr

    Neils bohr
    Bohr discovered that electrons could move around a nucleus in discrete energy called orbitals.radiation is emitted during movernment from one orbital to another.
  • Ernest Rutherford

    Ernest Rutherford
    Ernest rutherford first identified protons in the atomic nucleus in 1914. he also transmutated a nitrogen atom into an oxygen atom for the first time.
  • James Chadwick

    James Chadwick
    james chadwick was the first person to discover neutrons, and the isotopes was identified. this was the complete basis for the periodic table.