Masurium (symbol Ma) was a name proposed for chemical element 43, which was eventually named technetium. Two of the discoverers of rhenium, Walter Noddack and Ida Tacke claimed to have at the same time (1925) discovered this element which they named after Masuria in Eastern Prussia, the region where Walter Noddack's family originated. Their claim of discovery was not generally accepted, and so the element was eventually named by the Italian chemists Carlo Perrier and Emilio Segrè who had detected in a sample of molybdenum that had been bombarded with deuterium nuclei. Recently, work by John T. Armstrong at NIST suggests that the Noddacks had indeed discovered element 43, but it is extremely unlikely that even if this view were to be widely accepted that their proposed name would be adopted at this late date. A chemical element, often called simply element, is a substance that cannot be divided or changed into different substances by ordinary chemical methods. ... General Name, Symbol, Number technetium, Tc, 43 Chemical series Transition metals Group, Period, Block 7, 5, d Density, Hardness 11500 kg/m3, NA Appearance Silvery gray metallic Atomic properties Atomic mass [98] u Atomic radius (calc. ... General Name, Symbol, Number Rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7 (VIIB), 6, d Density, Hardness 21020 kg/m3, 7 Appearance grayish white Atomic properties Atomic weight 186. ... Walter Noddack (* 17 August 1893 in Berlin, 7 December 1960 in Berlin) was a German chemist. ... 1925 was a common year starting on Thursday (link will take you to calendar). ... Emilio Gino Segrè (February 1, 1905 - April 22, 1989) was an Italian American physicist who, with Owen Chamberlain, won the 1959 Nobel Prize in Physics for their discovery of the antiproton. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metal Group, Period, Block 6 (VIB), 5, d Density, Hardness 10280 kg/m3, 5. ... Deuterium (symbol 2H) is a stable isotope of hydrogen with a natural abundance of one atom in 6500 of hydrogen. ... As a non-regulatory agency of the United States Department of Commerce’s Technology Administration, the National Institute of Standards (NIST) develops and promotes measurement, standards, and technology to enhance productivity, facilitate trade, and improve the quality of life. ...

External links

• pubs.acs.org – ACS article on validity of Noddack and Tacke's discovery (http://pubs.acs.org/cen/80th/technetium.html)