97
Bk
Berkelium
247
Berkelium (Bk)
ActinidePeriod 7f-block-blockRadioactive
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. It is named after the city of Berkeley, California, the location of the University of California Radiation Laboratory where it was discovered in December 1949.
Latin name: Berkelium
Atomic Number
97
Atomic Mass
247 g/mol
Phase (STP)
Solid
Electron Config.
[Rn] 5f⁹ 7s²
General
SymbolBk
Atomic Number97
Atomic Mass247 g/mol
CategoryActinide
Period7
Blockf-block
Electron Configuration[Rn] 5f⁹ 7s²
Valence Electrons11
Coloursilvery-white (radioactive)
Appearancesilvery
CAS NumberCAS7440-40-0
Physical Properties
Phase (STP)Solid
Density14.78 g/cm³
Melting Point712.85°C · 1315.13°F · 986.00 K
Boiling Point2353.85°C · 4268.93°F · 2627.00 K
Atomic Properties
Atomic Radius244 pm
Electronegativity1.3 Pauling
Ionization Energy601 kJ/mol
Oxidation States+3, +4
Ion ChargeBk3+/Bk4+
Crystal Structure
Crystal Structureface-centered cubic
Nuclear & Hazards
RadioactiveYes
Half-life1.38×10^3 years (Bk-247)
Abundance
In Earth's Crust0.00000000000001%
Discovery & History
Discovery Year1949
Discovered ByStanley G. Thompson, Glenn T. Seaborg, Albert Ghiorso, and Kenneth Street Jr.
Country of DiscoveryUSA
Isotopes of Berkelium
| Isotope | Abundance | Half-life | Decay |
|---|---|---|---|
| Bk-247 | — | 1380 years | α |
| Bk-248 | — | ~300 years | α |
| Bk-249 | — | 330 days | β⁻ |