Berkelium

SYMBOL Bk PERIOD 7 SERIES NAME Actinide ATOMIC NO 97 

ATOMIC MASS 247 amu VALENCE 3 and 4 OXIDATION STATE -1-3 and -1-4 NATURAL STATE Solid 

ORIGIN OF NAME Named after the nuclear laboratory and the town in which the laboratory is located Berkeley, California. 

ISOTOPES There are a total of 23 isotopes of berkelium, none of which are found in nature or are stable. Their half-lives range from 600 nanoseconds for Bk-242 to 1,389 years for Bk-247, which is also the most stable isotope that by alpha decay transmutates into americium-243. 

Berkelium is a metallic element located in group 11 (IB) of the transuranic subseries of the actinide series. Berkelium is located just below the rare-earth metal terbium in the lanthanide series of the periodic table. Therefore, it has many chemical and physical properties similar to terbium ( Tb). Its isotopes are very reactive and are not found in nature. Only small amounts have been artificially produced in particle accelerators and by alpha and beta decay. 

Access Excellence the National Health Museum. About Biotech. 1992. Winding Your Way through DNA Symposium. Available from http //www.accessexcellence. org/AB/CC/bergpres.html . 

MELTING POINT 986°C BOILING POINT Unknown DENSITY Unknown MOST COMMON IONS Bk +, Bk  

Seaborg returned to the University of California at Berkeley in 1971. There, in 1974, he discovered with his colleagues one more element. Although it was a controversial discovery due to competing claims, the element was eventually named seaborgium (with the result that prior to his death in 1999, Clenn Seaborg was the only living person after whom an element had been named). 

In his career he was president of both the American Chemical Society and the American Association for the Advancement of Science. Because of his belief in the importance of education, he tmdertook to reform the chemistry and science curricula of high schools. CHEM Study, a project designed to improve the teaching of chemistry at the high school level, became an internationally recognized educational resource under his direction. He was a founder of CEMS (Creat Explorations in Math and Science) and many other science education projects. 

Seaborg worked hard to ensure that science education was not slighted and that science would be seen as a tremendous boon to humanity. Along these lines, it was his leadership that helped to bring into existence the Lawrence Hall of Science at Berkeley as a tribute to Ernest Orlando Lawrence, see also Americium Curium Lawrence, Ernest Plutonium. 

Asimov, Isaac (1989). Asimov s Chronology of Science and Discovery. New York Harper Row. 

and Goldwhite, Harold (1995). Creations of Fire Chemistry s Lively History from Alchemy to the Atomic Age. New York Plenum Press. 

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In the actinides, the element curium, Cm, is probably the one which has its inner sub-shell half-filled and in the great majority of its compounds curium is tripositive, whereas the preceding elements up to americium, exhibit many oxidation states, for example -1-2, -1-3. -1-4, -1-5 and + 6, and berkelium, after curium, exhibits states of -1- 3 and -E 4. Here then is another resemblance of the two series. 

Actinium 22 Thorium Protactinium M.04 Uranium 23g.lL1 Neptunium ( -i Plutonium i244 Americium 211 Curium -247i Berkelium -24- Californium 25H Einsteinium 252 Fermium IS Meodeievium 1258 Nobelium 25G... 

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