Bohrium (Bh): Electron Configuration and Properties

107Bh[270]
Transition metal

Bohrium (Bh): Electron Configuration and Properties

Electron configuration [Rn] 7s2 5f14 6d5 · group 7 · period 7 · Ar [270]

Bohrium data

Atomic number
107
Relative atomic mass
[270]
Group
7
Period
7
Block
d
Category
Transition metal
Electron configuration
[Rn] 7s2 5f14 6d5
Full configuration
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d5
Electrons per shell
2, 8, 18, 32, 32, 13, 2 (K L M N O P Q)
Valence electrons
7
Electronegativity (Pauling)
no data
First ionisation energy
no data
Atomic radius (van der Waals)
no data
State at room temperature
Solid
Melting point
no data
Boiling point
no data
Density
no data
Common oxidation states
+7, +5, +4, +3
Discovered
1976

Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.

Electron shell diagram

Bh

K 2 · L 8 · M 18 · N 32 · O 32 · P 13 · Q 2

Orbital diagram (outer electrons)

[Rn]↑↓7s2↑↓↑↓↑↓↑↓↑↓↑↓↑↓5f14↑↑↑↑↑6d5

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About bohrium

Bohrium, symbol Bh, is element number 107 in the periodic table. It is a transition metal in group 7, period 7, d-block. The element was discovered in 1976. It is named after Niels Bohr. Its bulk properties have never been measured because only a few atoms have been made; it is expected to be a solid at room temperature.

Bohrium electron configuration

The electron configuration of bohrium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d5, or in short [Rn] 7s2 5f14 6d5. Its electrons occupy 7 shells: K = 2, L = 8, M = 18, N = 32, O = 32, P = 13, Q = 2. For transition metals, valence electrons are counted from the 7s and 6d subshells: 2 + 5 = 7, matching group 7. For this superheavy element the configuration is a theoretical prediction.

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) → 5f14(102) → 6d5(107)

Uses of bohrium

Bohrium has no practical use outside research, because it can only be made a few atoms at a time in particle accelerators.

Safety

Only a handful of bohrium atoms have ever been made and they decay very quickly, so it is never handled in an ordinary laboratory.

Other elements in group 7

Frequently asked questions

What is the electron configuration of bohrium?

The electron configuration of bohrium (Bh, atomic number 107) is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d5, or [Rn] 7s2 5f14 6d5 in short. By shell: 2, 8, 18, 32, 32, 13, 2.

How many valence electrons does bohrium have?

Bohrium has 7 valence electrons.

Which group and period is bohrium in?

Bohrium is in group 7, period 7, d-block.

What is the atomic mass of bohrium?

Bohrium has no stable isotope, so the mass number of its longest-lived isotope, [270], is given.

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