Discovery date : 1949
Discovered by: Stanley Thompson, Albert Ghiorso, and Glenn Seaborg
Origin of the name: Berkelium was named after the town Berkeley, California, where it was first made.
Allotropes :
~>BERKELIUM is a transuranic radioactive chemical element with symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series.is a transuranic radioactive chemical element with symbol Bk and atomic number 97. It is a member of the actinide and transuranium element series.
| FACT BOX | |||
| Group | Actinides | Melting point | 986°C, 1807°F, 1259 K |
| Period | 7 | Boiling point | Unknown |
| Block | f | Density (g cm−3) | 14.78 |
| Atomic number | 97 | Relative atomic mass | [247] |
| State at 20°C | Solid | Key isotopes | 247Bk, 249Bk |
| Electron configuration | [Rn] 5f97s2 | CAS number | 7440-40-6 |
| ChemSpider ID | 22409 | ChemSpider is a free chemical structure database | |
Berkelium was first produced in December 1949, at the University of California at Berkeley, and was made by Stanley Thompson, Albert Ghiorso, and Glenn Seaborg. They took americium-241, which had first been made in 1944, and bombarded it with helium nuclei (alpha particles) for several hours in the 60-inch cyclotron. The americium itself had been produced by bombarding plutonium with neutrons.
The Berkeley team dissolved the target in acid and used ion exchange to separate the new elements that had been created. This was the isotope berkelium-243 which has a half-life of about 5 hours. It took a further nine years before enough berkelium had been made to see with the naked eye, and even this was only a few micrograms. The first chemical compound, berkelium dioxide, BkO2, was made in 1962.