1800-1875


  1. John Dalton
  2. Dmitri Mendeleyev
  3. George Stoney


John Dalton john_dalton.jpgDalton_atomic_symbols.jpg


Dalton who never settled for anything less than perfect. He always found what he was looking for in an experiment. Dalton discovered the atomic weights to six elements which were, hydrogen, oxygen, nitrogen, carbon, sulfur and phosphorous. And in 1803 it is written in his journal that he discovered water, ammonia and carbon dioxide's relative weights as well.

Dmitri Mendeleev



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Dates: February 1834- Febrary 1907

Discovery time period: 1869

Discovery: Periodic Table of elements

Mendeleev was the frist person to makethe periodic table of elements. He arranged them according to atomic weight and predicted the properties. In theis periodic table of elements he left spaces where elements had not been discovered yet. The element Mendelvian was named after him in 1955.

George Stoney

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Dates:1826-1911
Discovery time period:1874
Discovery: The electron


Stoney was a scientist who helped with the study of the spectra, which is light of various colors. His most significant work is the magniude of what is now the electron or electrically charged particle. In 1874 he calculated the magnitude by obtaining data from the electrolysis of water. This was one of the three fundemental units that contributed to the whole system.