Artificial radioactive element m.p. ? b.p. ? density estimated 14 g/cc; 874 pound/cubic foot	memory peg
	1949 Stanley G. Thompson and co-workers, Berkeley, Calif., USA
	Berkeley, town in California

First prepared in 1949 by Stanley G. Thompson, Albert Ghiorso, & Glenn T. Seaborg at the Berkeley Laboraty of the University of California by bombardment of Americium with Helium ions.

"A name was given to element 97 immediately; in fact, you might say that a name had been chosen even before it was discovered. According to the actinide concept, element 97 is the chemical homolog of terbium, which was named after the Swedish town of Ytterby. So the name «berkelium» after the city of Berkeley practically leaped out. However, the mayor of Berkeley displayed a complete lack of interest when he was called with the glad tidings. Stan and Al Ghiorso wanted to give berkelium the chemical symbol Bm, because it had been such a stinker in resisting identification for so long, but cooler heads prevailed and the symbol Bk was finally accepted by the scientific world." (note)

In his autobiography, Seaborg says more about the naming of Berkelium (note) :

Element 97's homolog among the rare earths is terbium, named for the town of Ytterby in Sweden, where many of the rare earths had been found and identified. Naming our new element analogously after Berkeley practically leaped out at us. I telephoned the mayor of Berkeley to share what I thought were glad tidings that the city would thus be immortalized on the periodic table as berkelium, news that he greeted with a complete lack of interest. Stan [Thompson] and Al [Ghiorso] suggested that berkelium's chemical symbol should be the letters Bm, because it had been such a stinker in resisting chemical identification for so long, but cooler heads prevailed to choose Bk.

The spelling of the name as Berkelium of Berklium caused some discussion. Thompson and his co-workers preferred to keep the second "e". The nomenclature committee of the National Research Council suggested dropping the second "e", thus spelling it as Berklium, and pronouncing it "berk'lium." The spelling remained in English as Thompson wanted, but the pronunciation varies, with berk'lium prominent in the United States and ber-ke-lium used more often in Europe. Several other languages, as you can see in the list to the left, dropped the second "e".

The town of Berkeley is the location of the Ernest Orlando Lawrence Berkeley National Laboratory, founded in 1931 (cf. lawrencium). The "Berkeley Lab", as it is called shortly, is managed by the University of California. At the foundation of this university in 1866, the town was named after the philosopher bishop George Berkeley (1685-1753).

The Lawrence Berkeley National Lab has been a leader in science and engineering technology for more than 70 years, serving as a powerful resource for the nation's scientific enterprise. Operated by the University of California for the U.S. Department of Energy, Berkeley Lab is dedicated to performing leading edge research in physics and cosmology, the life sciences, materials and chemistry, computing, and energy science, the Laboratory also operates unique user facilities available to qualified investigators, including the Advanced Light Source, the National Center for Electron Microscopy, the National Energy Research Scientific Computing Center, and the 88-Inch Cyclotron. The oldest of the Department of Energy national labs, Berkeley Lab has the distinction of being located next to one of the world's foremost universities-the University of California at Berkeley. See their website.

The name Berkelium did not go uncontested. А.П. Знойко (A.P. Znoyko) and V.I. Semishin, claimed the right to name element #97 because they had predicted its radioactive decay properties two years before its discovery using their Mendeleev periodic system of atomic nuclei (note) . They suggested that it therefore be given the name Mendelevium (symbol Md). Five years later the name Mendelevium was ascribed to element #101.

John and Gordon Marks suggested in 1994 the name Illinium (Il) after Illinois, where the actinides were discovered (since element 98 was named Californium after the other state where these discoveries were made). The Marks brothers found the old names ugly and confusing. They offered alternative names that are equivalent contemporary (at the time and place of discovery) metaphors, both more euphonious and more memorable (note).

False transuranic elements (#93-97)

Element #97 has got in 1934-38 the preliminary name Eka-Gold (Eka-Aurum) by Otto Hahn, Lise Meitner and Fritz Strassmann in Germany, who thought they had found traces of several transuranium elements. In December of 1938, Hahn and Strassman found out that these radioactivities were not due to transuranium elements but were due to fission products. According to the Periodic Table of that time, without the Actinide series, element #97 is below Gold (#79). According to the present Table, Eka-Gold would be #111.

The Polish name Bekerel

In may (older) Polish sources element #97 is named Bekerel. Krzysztof W. Zieliński wrote me on 18 January 2003 about this:

"The Polish name (and the international name) of the 97th element is «berkel» (...). It is true, that in older popular scientific Polish books the name of the 97th element was erroneously written «bekerel» and explained as derived from the French scientist's name «Becquerel». But it was evident mistake. The source of this mistake probably raised from the fact that the name «Becquerel» was well-known in Poland, because he worked together with Maria Sklodowska-Curie (...). In the second volume of the new Polish Great Encyclopaedia (Warsaw, 2002), the Polish name of the 97th element is «berkel»."

Further reading:

• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 848-850.
• Stanley G. Thompson, Albert Ghiorso, & Glenn T. Seaborg, The New Element Berkelium (Atomic Number 97). DOE-report. April 26, 1950. (Full text in PDF available on-line).
• Earl K. Hyde & Glenn T. Seaborg, Transurane : Teil A 1, I: Die Elemente. Gmelins Handbuch der anorganische Chemie, Ergänzungswerk zur 8. Aufl.; Band 7a. Weinheim/Bergstrasse: Chemie, 1973.
• Glenn T. Seaborg, "Stanley G. Thompson: a Chemist's Chemist." Chemtech 7 (1978), p. 408-413. (on-line).
• Glenn T. Seaborg, Early History of LBNL, A transcript of the lecture on the 65th Anniversary of Lawrence Berkeley National Laboratory, August 26, 1996 (on-line).