Berkelium

Main article: Isotopes of berkelium
iso	NA	half-life	DM	DE (MeV)	DP
²⁴⁵Bk	syn	4.94 d	ε	0.810	²⁴⁵Cm
²⁴⁵Bk	syn	4.94 d	α	6.455	²⁴¹Am
²⁴⁶Bk	syn	1.8 d	α	6.070	²⁴²Am
²⁴⁶Bk	syn	1.8 d	ε	1.350	²⁴⁶Cm
²⁴⁷Bk	syn	1380 y	α	5.889	²⁴³Am
²⁴⁸Bk	syn	>9 y	α	5.803	²⁴⁴Am
²⁴⁹Bk	syn	330 d	α	5.526	²⁴⁵Am
			SF	-	-
			β^-	0.125	²⁴⁹Cf

References

Berkelium (IPA: /bəˈkiːliəm/) is a synthetic element in the periodic table that has the symbol Bk and atomic number 97. A radioactive metallic element in the actinide series, berkelium was first synthesized by bombarding americium with alpha particles (helium ions) and was named after Berkeley, California and the University of California, Berkeley. Berkelium was the fifth transuranic element to be synthesized.

1 Notable characteristics
2 History
3 Isotopes
4 References
5 External links

[edit] Notable characteristics

Weighable amounts of ²⁴⁹Bk (half-life 314 days) make it possible to determine some of its properties using macroscopic quantities. As of 2004 it had not been isolated in its elemental form, but it is predicted to be a silvery metal that would easily oxidize in air at elevated temperatures and would be soluble in dilute mineral acids.

X-ray diffraction techniques have been used to identify various berkelium compounds such as berkelium dioxide (BkO₂), berkelium fluoride (BkF₃), berkelium oxychloride (BkOCl), and berkelium trioxide (BkO₃). In 1962 visible amounts of berkelium chloride (BkCl₃) were isolated that weighed 3 billionths of a gram. This was the first time visible amounts of a pure berkelium compound were produced.

Like other actinides, berkelium bio-accumulates in skeletal tissue. This element has no known uses outside of basic research and plays no biological role.

[edit] History

Berkelium was first synthesized by Glenn T. Seaborg, Albert Ghiorso, Stanley G. Thompson, and Kenneth Street, Jr at the University of California, Berkeley in December 1949. The team used a cyclotron to bombard a milligram-sized target of ²⁴¹Am with alpha particles to produce ²⁴³Bk (half-life 4.5 hours) and two free neutrons. One of the longest lived isotopes of the element, ²⁴⁹Bk (half-life 330 days), was later synthesized by subjecting a ²⁴⁴Cm target with an intense beam of neutrons.

[edit] Isotopes

19 radioisotopes of berkelium have been characterized, with the most stable being ²⁴⁷Bk with a half-life of 1380 years, ²⁴⁸Bk with a half-life of >9 years, and ²⁴⁹Bk with a half-life of 330 days. All of the remaining radioactive isotopes have half-lifes that are less than 5 days, and the majority of these have half lifes that are less than 5 hours. This element also has 2 meta states, with the most stable being ^248mBk (t_½ 23.7 hours). The isotopes of berkelium range in atomic weight from 235.057 amu (²³⁵Bk) to 254.091 amu (²⁵⁴Bk).