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What is Berkelium

Berkelium (pronounced as BURK-lee-em) is a radioactive metal belonging to the family of actinides and denoted by the chemical symbol Bk. Out of its 12 isotopes, berkelium-247 and berkelium-249 are relatively more stable with a half-life of 1380 years and 320 days, respectively.



Origin of its Name: It has been named after the city of Berkeley in California.

Who Discovered Berkelium: Stanley Thompson, Glenn Seaborg, and Albert Ghiorso were the discoverers of the element.

When and Where was it Discovered

In December 1949 at the University of California in Berkeley, Thompson, Seaborg, and Ghiorso bombarded americium-241 with alpha particles in a cyclotron for several hours. They dissolved the target in acid and isolated berkelium-243 using ion exchange technique that had a half-life of 5 hours. After nine years, only a few micrograms of the new element were produced to be visible to the naked eye.

Berkelium Element

Classification and Position of the Element on the Periodic Table [1]

Group 17
Period 6
Block p

Properties and Characteristics of Berkelium

General Properties

Relative atomic mass/weight 247 [1]
Atomic mass 247 atomic mass units [5]

Physical Properties

Color/appearance Silver white [3]
Luster Metallic [3]
Odor Unknown [3]
Melting point/freezing point 986°C (1807°F) [1]
Boiling point Unknown [1]
Density 14.78 g/cm[1]
State at room temperature (25°C) (solid/liquid/gas) Solid [1]
Thermal conductivity 10 W m-1 K-1 [3]
Electrical conductivity Unknown [3]

Chemical Properties

Flammability Unknown
Oxidation states 4, 3 [1]

Atomic Data of Berkelium

Atomic number 97 [1]
Valence electrons 2 [4]
Electron configuration (noble gas configuration) [Rn] 5f9 7s2 [1]
Atomic structure
– Number of Electrons 97 [3]
– Number of Neutrons 150
– Number of Protons 97
Radius of atom
– Atomic Radius 2.44 Å [1]
– Covalent Radius 1.68 Å [1]
Ionization energy


1st 2nd 3rd 4th 5th 6th 7th

Berkelium Bohr Model

Uses of Berkelium

Since only minute amounts of the element are produced in the laboratory by bombardment of neutrons with plutonium-239 in reactors, its use is limited only to basic scientific studies [1].

Berkelium Hazards

Bk may have adverse effects when accidentally inhaled or ingested due to its radioactivity.

Interesting Facts

Berkelium chloride was its first visible compound produced in 1962 that weighed about 3 billionths of a gram [2].

Pictures of Berkelium



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