||Historical Background -
Romantic (1820-1900 AD)
|1826 AD||Berzelius proposes new system of symbolic notation.|
|1831||Faraday discovers electromagnetic induction and devises the first electrical generator. Begins work on electrolysis.|
|1832||Faraday introduces the terms electrode, anode, cathode, ion.|
|1833||Faraday announces the
laws of electrolysis.
At a meeting of the British Association for the Advancement of Science, William Whewell proposes the term ‘scientist.’
|1838||Charles Goodyear invents vulcanized rubber.|
|1846||In a short paper “Thoughts on Ray Vibrations,” Faraday discusses the possibility of doing away with the 'aether'.|
|1847||Hermann Helmholtz proposes the law of the conservation of energy (the first law of thermodynamics).|
|1848||William Thomson (later Lord Kelvin) calculates the absolute zero point of temperature.|
|1852||Faraday publishes “On
the Physical Character of the Lines of Magnetic Force,” charging that
Newtonian science is an obstacle to the progress of science.
Edward Frankland, first paper on organo-metallics and first mention of the theory of valency.
publishes his paper on bonding in carbon compounds.
Stanislas Cannizzaro resurrects Avogadro’s hypothesis.
|1860||Marcellin Berthelot synthesizes new organic molecules
ethyl alcohol, methyl alcohol) from the elements, adding another blow
First meeting of the International Chemical Congress at Karlsruhe.
Kekulé proposes a ring structure for benzene, reportedly
after dreaming about six monkeys holding one another by the tail.
Clausius coins the term “entropy” and states the first two laws of thermodynamics as “the energy of the universe is constant” and “the entropy of the universe tends to a maximum.”
|1866||Leclanché invents the electrical battery (dry cell).|
|1869||Dmitri Mendeleev proposes his periodic table of the elements, predicting the existence of three new elements (gallium, scandium, and germanium).|
|1871||Eugen Goldstein submits that cathode radiation sustains a
interpretation of matter.
Cromwell Varley submits that cathode radiation sustains a particulate theory.
|1874||Kelvin formally states the second law of thermodynamics.
Joseph Achille Le Bel and Jacobus van’t Hoff independently propose that the molecule has a three-dimensional structure (stereochemistry).
|1875||In a zinc ore mined in the Pyrenees, Lecoq de Boisbaudran
discovers gallium, in support of Mendeleev.
Winkler discovers germanium, in support of Mendeleev.
Crookes claims that cathode radiation points to a fourth state of matter that is particulate in nature.
|1876||Julius Plücker describes the phenomenon of cathode rays and is the first to use the term.|
|1879||Nilson discovers scandium, in support of Mendeleev.|
|1887||Foundation by Friedrich Ostwald of the Zuitschrift für physikalische Chemie, marking establishment of the discipline of physical chemistry.|
|1888||Hertz demonstrates propagation of electromagnetic waves (radio waves).|
|1891||George Johnstone Stoney suggests the term ‘electron’ for unit of electricty.|
|1892||(to 1904) Konrad Lorenz develops his electron theory.|
|1895||William Ramsay and William Crookes identify the element
Wilhelm Wilhelm Conrad Röntgen discovers X-rays which were immediately used to visualize bodily structures.
|1896||Antoine Henri Becquerel discovers natural radioactivity in uranium salts.|
|1897||JJ Thomson shows that electrons are independent particles.|
|1898||Marie and Pierre Curie isolate the radioactive elements of
radium and polonium
John Sealy Townsend measures the charge of an electron.
|1899||Alpha and beta rays shown by Ernest Rutherford to be distinct
types of radiation.
Rutherford notices thorium emanation.
Paul-Ulrich Villard observes gamma rays.