Berkelium: An Element Born in the Lab
What is Berkelium?
Berkelium is a synthetic chemical element, meaning it does not occur naturally on Earth. It is a radioactive, metallic element with the atomic number 97 and the chemical symbol Bk. Berkelium belongs to the actinide series, a group of metallic elements typically found at the bottom of the periodic table, known for their radioactivity. Because it is synthetic and radioactive, only microscopic quantities of Berkelium have ever been produced. Its physical appearance is predicted to be a silvery metal, similar to other actinides, but this has been difficult to observe due to its scarcity and intense radioactivity.
The Story of its Discovery and Name
Berkelium was first synthesized and identified in December 1949 by a team of scientists at the University of California, Berkeley, in the United States. The research group included Glenn T. Seaborg, Albert Ghiorso, Stanley G. Thompson, and Kenneth Street Jr. They created Berkelium by bombarding a very small sample of americium-241 (another synthetic element) with alpha particles (helium nuclei) using a cyclotron, a type of particle accelerator. The name “Berkelium” was chosen to honor the city of Berkeley, California, where this significant scientific breakthrough occurred. This naming convention is similar to how the element Californium was named after the state of California, or how Americium was named after the continent of America.
Berkelium at a Glance
- Chemical Symbol: Bk
- Atomic Number: 97
- Nature: Berkelium is a synthetic element, meaning it must be created in a laboratory and is not found in nature.
- Radioactivity: All known isotopes of Berkelium are radioactive, meaning they spontaneously decay over time by emitting particles and energy. This decay process limits how long samples can be studied and requires specialized handling.
- Scarcity: Only very small, milligram quantities of Berkelium have ever been produced worldwide, making it one of the rarest and most expensive elements.
- Primary Use: Berkelium is primarily used in scientific research. For example, berkelium-249 served as a target material to synthesize Tennessine (Ts), element 117, at the Joint Institute for Nuclear Research in Dubna, Russia, and Oak Ridge National Laboratory in the U.S. Tennessine itself was named after the U.S. state of Tennessee, where parts of the research took place.
- Expected Properties: Although difficult to study directly, scientists predict Berkelium exhibits properties similar to its lanthanide counterpart, Terbium, including a metallic luster and reactivity with various acids.