![]() By early 1869 Mendeleev had arrived at the concept that trends in properties of elements corresponded to increases in their atomic weights. When Mendeleev first began writing his textbook from 1867–1869, he formulated a framework for thinking about the elements, which included, among other ideas, an abstract conception of a chemical element using its atomic weight as the fundamental feature that determined its chemical energy and consequently also its chemical properties. In contrast to Kedrov’s view of the discovery taking place on one day, a credible case can be made for a longer process of discovery that lasted well over a year. Also, Kedrov’s emphasis on Mendeleev’s comparison of various natural families of elements by the atomic weights of their members is likewise implausible because many of these groups did not have clearly established weights and other properties in 1869. Kedrov’s belief that the key step in the discovery involved the alkali metals and what elements to discuss after this group is implausible, because no hesitation can be noted in Mendeleev’s prior plans for his textbook and the chemical properties of the alkali earths make them the natural successors, despite some other elements having a few similar properties. In addition, Kedrov tended to overlook the evidence provided in Mendeleev’s textbook as a guide to his thoughts during the months surrounding 17 February. However, the evidentiary basis of this reconstruction is shaky, because the few archival documents Kedrov used cannot definitively be dated to that one day and may not even refer to the incidents claimed by Kedrov. ![]() Kedrov provided an extremely detailed, almost hour-by-hour recreation of the so-called day of one great discovery. Provided alternate views of Mendeleev’s discovery. There are serious deficiencies with Kedrov’s account that are beginning to be recognized and discussed by a larger group of scholars, even though a few historians of chemistry (mainly residing in St. At the end of the day, he drafted a clean copy of his table of elements and sent it to be printed. To help in this process, he made a series of cards on which he wrote the symbols and main properties of the sixty-three then-known elements and began to play what Kedrov called chemical solitaire. Over the course of this day, Mendeleev increased the numbers of elements he was able to arrange in groups in several rough drafts of a table. On 17 February, he began to compare the atomic weights of these various groups of elements, which Kedrov identified as the key step in the discovery of the periodic law. ![]() The logical choice was the alkaline earth metals, but some other metals had similar properties, so Mendeleev would have to choose which way to proceed. He was then faced with what group to consider next. By early in 1869, Mendeleev had finished the first part of the textbook, ending with a chapter on the halogens, and moved on to the alkali metals. Petersburg University and was writing his own general chemistry textbook for use in his classes. Mendeleev had recently been appointed to the chair of chemistry at St. In brief, Kedrov argued that Mendeleev formulated the main contours of the periodic law during the course of one day, 17 February 1869 on the Russian calendar (1 March by the Gregorian calendar in use in the West). Kedrov’s article in the original Dictionary of Scientific Biography (1981 DSB) brought his conception of the discovery of the periodic law to a broader audience and this view has since become widely accepted by many scholars. All of these provide a fuller context in which to better understand his central scientific contributions. Interest in Mendeleev’s work has continued in the early twenty-first century, and a small but steady stream of studies continues to flow from scholars both inside and outside of Russia.Īlthough a considerable part of the work on Mendeleev’s output considers the various aspects of the periodic law and its discovery-his most important contribution to science-there is a growing interest in Mendeleev’s scientific work for the Russian government, his involvement with practical issues of agriculture and industry, his critique of spiritualism, and his scientific research on the theory of solutions and on gas laws, among other aspects of his life and work. ![]() Recognition of Mendeleev as the most important, although not the only, developer of the periodic law has strengthened in recent years, and his contributions to other areas of science and learning have begun to be explored in greater detail by scholars. For the original article on Mendeleev see DSB, vol. Petersburg, Russia, 2 February 1907),Ĭhemistry, periodic table. Tobolsk, Siberia, Russia, 8 February 1834 d. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |