Berkelium (Bk): Electron Configuration, Properties and Uses
Berkelium (Bk): Electron Configuration, Properties and Uses
Electron configuration [Rn] 7s2 5f9 · f-block, actinide series · period 7 · Ar [247]
Berkelium data
- Atomic number
- 97
- Relative atomic mass
- [247]
- Group
- – (actinide series)
- Period
- 7
- Block
- f
- Category
- Actinide
- Electron configuration
- [Rn] 7s2 5f9
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f9
- Electrons per shell
- 2, 8, 18, 32, 27, 8, 2 (K L M N O P Q)
- Valence electrons
- 2 (in the outer shell)
- Electronegativity (Pauling)
- 1.3
- First ionisation energy
- 6.23 eV
- Atomic radius (van der Waals)
- 244 pm
- State at room temperature
- Solid
- Melting point
- 1050 °C
- Boiling point
- no data
- Density
- 14 g/cm³
- Common oxidation states
- +4, +3
- Discovered
- 1949
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 18 · N 32 · O 27 · P 8 · Q 2
Orbital diagram (outer electrons)
About berkelium
With atomic number 97, berkelium (Bk) has 97 protons in its nucleus and 97 electrons as a neutral atom. It belongs to the actinide series in period 7 (f-block), usually shown below the main table. The element was discovered in 1949. It is named after Berkeley, California. Berkelium is a solid at room temperature, melting at 1050 °C.
Berkelium electron configuration
The electron configuration of berkelium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f9, or in short [Rn] 7s2 5f9. Its electrons occupy 7 shells: K = 2, L = 8, M = 18, N = 32, O = 27, P = 8, Q = 2. As an actinide, berkelium fills the 5f subshell. Its outer 7s subshell holds 2 electrons; valence electrons for this series are not assigned by the usual group rule. When it forms cations, electrons leave the outermost subshell first: Bk3+ = [Rn] 5f8.
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12) → 3p6(18) → 4s2(20) → 3d10(30) → 4p6(36) → 5s2(38) → 4d10(48) → 5p6(54) → 6s2(56) → 4f14(70) → 5d10(80) → 6p6(86) → 7s2(88) → 5f9(97)
Uses of berkelium
In industry and the laboratory, berkelium turns up in many places, for example target material for making heavier elements, such as tennessine (117).
Safety
Berkelium is radioactive. Using, storing or transporting radioactive material requires a licence from the national regulator (BAPETEN in Indonesia). Always read the safety data sheet (SDS) before working with a chemical.
Other actinides
Frequently asked questions
What is the electron configuration of berkelium?
The electron configuration of berkelium (Bk, atomic number 97) is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f9, or [Rn] 7s2 5f9 in short. By shell: 2, 8, 18, 32, 27, 8, 2.
How many valence electrons does berkelium have?
Berkelium has 2 electrons in its outer shell. For lanthanides and actinides, valence electrons are not assigned by the usual group rule.
Which group and period is berkelium in?
Berkelium is in the actinide series, period 7, f-block.
What is the atomic mass of berkelium?
Berkelium has no stable isotope, so the mass number of its longest-lived isotope, [247], is given.
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