Berkelium Electron Configuration

Reference for berkelium's electron configuration: [Rn] 5f⁹ 7s² (full: 1s²…6p⁶ 5f⁹ 7s²). Includes orbital filling table, shell breakdown, and key atomic data.

Z = 97 Bk Berkelium

Berkelium — Electron Configuration

Atomic number 97 · Actinide series · Period 7 · f-block

[Rn] 5f⁹ 7s² 97 electrons 11 outer e⁻ Synthetic

5f Filling in Berkelium

Berkelium follows standard Aufbau filling: after the [Rn] core, electrons populate the 5f subshell. With nine 5f electrons, Bk sits near the middle of the actinide row. Unlike actinium (Z=89), which anomalously places its 89th electron in 6d, berkelium's 97 electrons fill 5f as expected. This makes Bk a true f-block actinide, and its 5f⁹ configuration gives it both +3 and +4 oxidation states — the latter being stable enough to observe in solution, which is rare among actinides.

Noble-Gas Shorthand

[Rn] 5f⁹ 7s²

[Rn] = 86-electron radon core.

Full Expanded Configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶ 5f⁹ 7s²

All 97 electrons written by subshell.

Subshell Breakdown

Subshell Type Electrons Capacity Notation
1s s orbital, shell n=1 2 2 1s²
2s s orbital, shell n=2 2 2 2s²
2p p orbitals, shell n=2 6 6 2p⁶
3s s orbital, shell n=3 2 2 3s²
3p p orbitals, shell n=3 6 6 3p⁶
3d d orbitals, shell n=3 10 10 3d¹⁰
4s s orbital, shell n=4 2 2 4s²
4p p orbitals, shell n=4 6 6 4p⁶
4d d orbitals, shell n=4 10 10 4d¹⁰
4f f orbitals, shell n=4 14 14 4f¹⁴
5s s orbital, shell n=5 2 2 5s²
5p p orbitals, shell n=5 6 6 5p⁶
5d d orbitals, shell n=5 10 10 5d¹⁰
6s s orbital, shell n=6 2 2 6s²
6p p orbitals, shell n=6 6 6 6p⁶
5f f orbitals, shell n=5 9 14 5f⁹
7s s orbital, shell n=7 2 2 7s²
Total 97

Valence subshells (5f and 7s) are highlighted. All others form the [Rn] core.

Shell Fill Summary

Shell 1 (n=1) — 1s² 2 / 2 electrons (100%)
Shell 2 (n=2) — 2s² 2p⁶ 8 / 8 electrons (100%)
Shell 3 (n=3) — 3s² 3p⁶ 3d¹⁰ 18 / 18 electrons (100%)
Shell 4 (n=4) — 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 32 / 32 electrons (100%)
Shell 5 (n=5) — 5s² 5p⁶ 5d¹⁰ 5f⁹ 27 / 50 electrons (54%)
Shell 6 (n=6) — 6s² 6p⁶ 8 / 18 electrons (44%)
Shell 7 (n=7) — 7s² 2 / 32 electrons (6%)

Summary

Reference for berkelium's electron configuration: [Rn] 5f⁹ 7s² (full: 1s²…6p⁶ 5f⁹ 7s²). Includes orbital filling table, shell breakdown, and key atomic data.

How it works

  1. Berkelium's 97 electrons fill orbitals in order of increasing energy following the Aufbau principle.
  2. Radon ([Rn], Z=86) provides the filled core: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 6s² 6p⁶.
  3. After the [Rn] core, the 5f subshell fills: berkelium has 5f⁹, nine electrons across the seven 5f orbitals.
  4. Two electrons occupy the 7s subshell, completing the ground-state configuration [Rn] 5f⁹ 7s².
  5. Unlike actinium (which anomalously fills 6d before 5f), berkelium follows standard 5f filling — it is a genuine f-block actinide.
  6. Valence electrons are 5f⁹ 7s², giving Bk common oxidation states of +3 and +4.

Use cases

  • Chemistry reference for students studying actinide or heavy-element configurations.
  • Verify the 5f filling pattern for mid-actinide elements during exam preparation.
  • Understand how berkelium differs from anomalous actinides like actinium and thorium.
  • Look up quantum numbers and subshell electron counts for the 5f series.
  • Teaching aid for periodic trends and f-block electron configurations.

Frequently Asked Questions

Last updated: 2026-07-08 · Reviewed by Nham Vu