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hennig brand
Although gold,silver,tin,copper,lead and mercury have been known since the olden days, phosphorus was the first discovery by a scientist called hennig brand, in 1649 -
John Dobereiner
John Dobereiner noticed that the atomic weight of strontium fell midway between the weights of calcium and barium -
Antoine Bequerel & Ernest Rutherford
In 1886 French physicist Antoine Bequerel first discovered radioactivity. Ernest Rutherford named three types of radiation; alpha, beta and gamma rays. Marie and Pierre Curie started working on the radiation of uranium and thorium, and subsequently discovered radium and polonium. They discovered that beta particles were negatively charged. -
Sir William Ramsay & Lord Rayleigh
In 1894 Sir William Ramsay and Lord Rayleigh discovered the noble gases, which were added to the periodic table as group 0. -
J.J Thomson
In 1897 English physicist J. J. Thomson first discovered electrons; small negatively charged particles in an atom. John Townsend and Robert Millikan determined their exact charge and mass. Read more: http://www.lenntech.com/periodic/history/history-periodic-table.htm#ixzz23bMNjGNF -
Niels Bohr
In 1913 Niels Bohr discovered that electrons move around a nucleus in discrete energy called orbitals. Radiation is emitted during movement from one orbital to another. -
Ernerst Rutherford
In 1914 Ernest Rutherford first identified protons in the atomic nucleus. He also transmutated a nitrogen atom into an oxygen atom for the first time. English physicist Henry Moseley provided atomic numbers, based on the number of electrons in an atom, rather than based on atomic mass. -
James Chadwick
In 1932 James Chadwick first discovered neutrons, and isotopes were identified. This was the complete basis for the periodic table. In that same year Englishman Cockroft and the Irishman Walton first split an atom by bombarding lithium in a particle accelerator, changing it to two helium nuclei.
