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John Dalton
http://en.wikipedia.org/wiki/Timeline_of_chemistry Dalton proposes the atomic theory. He believed that this could help explain the many mysteries of water, like how it absorbs carbon dioxide better than nitrogen. -
Lord Kelvin
http://en.wikipedia.org/wiki/Timeline_of_chemistry Kelvin introduces the scale of absolute zero. This is considered to be the temperature that molecular motion actually stops. -
Dmitri Mendeleev
http://en.wikipedia.org/wiki/Timeline_of_chemistry Mendeleev creates the first periodic table. It consisted of 66 elements all organized neatly by atomic weights. -
William Ramsay
http://en.wikipedia.org/wiki/Timeline_of_chemistry Ramsay discovers the noble gases of the periodic table. With this discovery comes models of chemical bonding and it also filled a large hole in the periodic table. -
Ernest Rutherford
http://en.wikipedia.org/wiki/Timeline_of_chemistry Rutherford discovers that all different types of radioactive decay occur with the same mathematical exponential formula. -
S. P. L. Sorenson
http://en.wikipedia.org/wiki/Timeline_of_chemistry Sorenson invented the pH scale and how to measure the acidity of liquids. On a scale of 1-14 with the lower numbers being very acidic, middle numbers are neutral, and the higher numbers being very basic -
Frederick Soddy
http://en.wikipedia.org/wiki/Timeline_of_chemistry Soddy proposes the theory of isotopes. Elements that differ in atomic weights but have the same chemical properties as the original elements. -
Niels Bohr
http://en.wikipedia.org/wiki/Timeline_of_chemistry Bohr creates the bohr model of an atom. The difference than the earlier models is now the electrons are contained in strictly defined orbitals. -
J. J. Thomson
http://en.wikipedia.org/wiki/Timeline_of_chemistry Thomson further researches in science and proposes mass spectrometry. This is a technique that uses a mass to charge ratio.