Jöns Jacob Berzelius
1779-1848
Swedish Chemist
The most renowned chemist of the first third of the nineteenth century, Jöns Jacob Berzelius excelled as a theorist, experimenter, teacher, designer of laboratory equipment, and disseminator of chemical information. He invented the modern system of chemical notation; named such chemical concepts as isomerism, isomorphism, allotropy, and catalysis; and discovered the chemical elements of cerium, selenium, and thorium.
Descended from three generations of Lutheran clergy, Berzelius lost his father at age two and his mother at age nine and was raised by relatives. He began medical studies in Uppsala in 1796 and completed them in 1802, thereafter making a meager living as a district doctor to the poor while working as an unpaidassistant to the professor of pharmacy at the School of Surgery in Stockholm. His fortunes improved upon succeeding to the professorship in 1807, which in 1810 was renamed a chair in chemistry.
Meanwhile, Berzelius had become friends with Wilhelm Hisinger, a prosperous mine owner. Together they undertook original researches using galvanic piles (the earliest batteries) to decompose numerous salts into their respective acidic and basic components, thereby greatly expanding the knowledge and techniques of inorganic analysis. Utilizing the newly formulated atomic theory of the British chemist John Dalton (1766-1844), Berzelius used these analytical results to establish both atomic weights and equivalent weights (the effective multiples of atomic weights for elements in chemical reactions) for more than two dozen elements, to previously unattained degrees of accuracy.
Extending Antoine Laurent Lavoisier's (1743-1794) previous systematic reform of chemical nomenclature for naming elements and compounds, Berzelius also simplified the existing unsystematic set of chemical symbols. He represented each element with the first letter of its Latin name and used a second significant letter when necessary to distinguish two or more elements with names having the same initial letter—e.g., C for Carbon, Ca for calcium, and Cu for copper (Latin "cuprum"). With minor alterations, this system is still in use today.
A triumphant visit to England in 1812 and meetings with its most eminent scientists secured Berzelius's international reputation. The year 1814 saw the first edition of his new classification of minerals according to chemical properties, which quickly replaced previous systems based on physical descriptions. In 1818-1819 he made a second trip abroad, to France, where he collaborated in research with leading chemists and completed a volume on chemical proportions in inorganic reactions. This formed a second part of what ultimately became the six-volume Textbook of Chemistry completed in 1830, which went through five editions and became a standard reference work.
While in France Berzelius was elected secretary of the Academy of Science in Stockholm, which doubled his salary and provided him with new laboratory facilities. In 1821 he founded an annual report on current chemical research throughout Europe, which he published each spring until his death in 1848. Generally known by its German title, the Jahresberichte, this became the single most important source of information for chemists of the era. In 1832 Berzelius resigned his other university obligations to concentrate on this work, and upon his belated marriage in 1835 was made a baronet.
Berzelius's most important theoretical contribution was his theory of electrochemical dualism. Classifying all elements as either electropositive or electronegative in character, he argued that all compounds resulted from combinations of these opposites and that a given element could substitute for another of the same electrical character in a compound. Initially this theory facilitated the explanation of a wide array of inorganic reactions, and aspects of it anticipated modern theories of polar bonding.
However, with the development of organic chemistry beginning in the 1830s, Berzelius's theory proved unable to explain how elements such as hydrogen and chlorine with supposedly opposite electrical characters could replace one another in organic compounds. Consequently the theory soon lost favor to the emerging rival substitution theories of chemical "types" and "radicals." Berzelius's reputation suffered as he refused to acknowledge the inadequacies of his system, used the Jahresberichte to violently attack his critics, and broke off long-standing friendships with Justus Liebig (1803-1873) and other chemists who opposed his views. However, his many lasting accomplishments and the work of his most prestigious students influenced chemistry for decades to come.
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