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Robert Wilhelm Eberhard Bunsen (German:; 30 March 1811 [a] – 16 August 1899) was a German chemist.He investigated emission spectra of heated elements, and discovered caesium (in 1860) and rubidium (in 1861) with the physicist Gustav Kirchhoff. [11]
Caesium (IUPAC spelling; [9] also spelled cesium in American English) is a chemical element; it has symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of 28.5 °C (83.3 °F; 301.6 K), which makes it one of only five elemental metals that are liquid at or near room temperature.
He and Bunsen discovered caesium and rubidium in 1861. [9] At Heidelberg he ran a mathematico-physical seminar, modelled on Franz Ernst Neumann's, with the mathematician Leo Koenigsberger . Among those who attended this seminar were Arthur Schuster and Sofia Kovalevskaya .
Perey discovered it as a decay product of 227 Ac. [177] Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. [178]
[31] [32] They demonstrated that spectroscopy could be used for trace chemical analysis and several of the chemical elements they discovered were previously unknown. Kirchhoff and Bunsen also definitively established the link between absorption and emission lines, including attributing solar absorption lines to particular elements based on ...
Clair Cameron Patterson (June 2, 1922 – December 5, 1995) [1] was an American geochemist.Born in Mitchellville, Iowa, Patterson graduated from Grinnell College.He later received his Ph.D. from the University of Chicago and spent his entire professional career at the California Institute of Technology (Caltech).
Caesium (Cs) 55 caesius: Latin "blue-gray" [43] or "sky blue" descriptive (colour) From Latin caesius, which means "sky blue". Its identification was based upon the bright-blue lines in its spectrum, and it was the first element discovered by spectrum analysis. Barium (Ba) 56 βαρύς (barys) Greek via Neo-Latin "heavy" βαρύς (barys ...
An image from John Dalton's A New System of Chemical Philosophy, the first modern explanation of atomic theory.. This timeline of chemistry lists important works, discoveries, ideas, inventions, and experiments that significantly changed humanity's understanding of the modern science known as chemistry, defined as the scientific study of the composition of matter and of its interactions.