Why does ytterbium have a completely filled 4f subshell?

Ytterbium is the second-to-last lanthanide. By Z=70, the 4f subshell has received all 14 electrons it can hold (two per each of the seven f orbitals). No exception disrupts this filling because a full 4f¹⁴ shell, like a half-filled shell, has extra exchange-energy stabilization. Ytterbium follows the Aufbau rule without exception: [Xe] 4f¹⁴ 6s².

What is the noble-gas shorthand for ytterbium?

The abbreviated notation is [Xe] 4f¹⁴ 6s², where [Xe] represents the xenon core (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶, 54 electrons). The remaining 16 electrons beyond xenon are 4f¹⁴ and 6s².

How many unpaired electrons does ytterbium have?

Zero. The 4f¹⁴ subshell is completely filled — all seven f orbitals each hold two paired electrons. The 6s² electrons are also paired. Ytterbium is therefore diamagnetic in its ground state, unlike most lanthanides which are paramagnetic.

Why does ytterbium form both +2 and +3 oxidation states?

The +3 state (Yb³⁺, [Xe] 4f¹³) is most common in coordination chemistry, formed by removing 6s² and one 4f electron. The +2 state (Yb²⁺, [Xe] 4f¹⁴) is more stable for ytterbium than for most lanthanides because the resulting ion retains a completely filled, closed-shell 4f¹⁴ configuration, which has extra stability. This makes Yb²⁺ compounds accessible, unlike Eu²⁺ being the only other common lanthanide +2 ion.

Why is ytterbium used in fiber lasers?

Yb³⁺ ions (4f¹³ configuration) have a simple two-level-like energy structure in the near-infrared. When doped into silica fiber or crystals, Yb³⁺ absorbs at ~976 nm and emits at ~1030 nm with very high efficiency (>80% quantum efficiency) and low quantum defect. Yb-doped fiber lasers are the dominant high-power CW laser technology for industrial cutting, welding, and scientific applications.

Is ytterbium a transition metal or a lanthanide?

Ytterbium is a lanthanide (rare-earth element) in period 6, f-block. It sits between thulium (Z=69) and lutetium (Z=71). Its filled 4f¹⁴ subshell means it has no 5d electrons in the ground state, which is why it chemically resembles the alkaline-earth metals more closely than many of its lanthanide neighbors.

What are the main uses of ytterbium?

The primary applications are: (1) Yb-doped fiber lasers and amplifiers at 1030 nm for industrial and scientific use; (2) optical lattice atomic clocks based on the narrow 4f¹⁴ → 4f¹³5d¹ transitions, among the world's most accurate clocks; (3) stainless steel alloying to improve grain refinement; (4) garnet crystals (Yb:YAG) for solid-state lasers; (5) as a portable x-ray source (Yb-169 isotope).

Ytterbium Electron Configuration

Name: Ytterbium Electron Configuration
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Author: Nham Vu

Reference tool for ytterbium's electron configuration ([Xe] 4f¹⁴ 6s²), orbital diagram, its completely filled 4f subshell, and properties including fiber laser and atomic clock uses.

Z = 70 Yb Ytterbium

Ytterbium — Electron Configuration

Atomic number 70 · Lanthanide · Period 6 · f-block · Completely filled 4f¹⁴

[Xe] 4f¹⁴ 6s² 70 electrons 0 unpaired electrons Diamagnetic

Completely filled 4f subshell

Ytterbium is the penultimate lanthanide. Its 4f¹⁴ subshell is completely full — all seven f orbitals doubly occupied, 14 electrons total. Combined with the outermost 6s², the ground-state configuration is [Xe] 4f¹⁴ 6s². There are no unpaired electrons, making ytterbium diamagnetic and giving it a closed-shell stability that allows an accessible +2 oxidation state (Yb²⁺ retains the full 4f¹⁴ core).

Subshell Breakdown

Subshell	Type	Electrons	Max 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 (part of Xe core)	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 (part of Xe core)	10	10	4d¹⁰
5s	s orbital, shell n=5	2	2	5s²
5p	p orbitals, shell n=5 (completes Xe core)	6	6	5p⁶
4f	f orbitals, shell n=4 — completely filled	14	14	4f¹⁴
6s	s orbital, shell n=6 (outermost)	2	2	6s²
Total		70

Full Configuration

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

All subshells written explicitly; 70 electrons total.

Noble-Gas Shorthand

[Xe] 4f¹⁴ 6s²

[Xe] = xenon core, 54 electrons (1s² through 5p⁶).

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 8 / 50 electrons (16%)

Shell 6 (n=6) — 6s² 2 / 72 electrons (3%)

Shells 1–4 are completely filled for ytterbium — the 4f subshell reaches its 14-electron maximum here. Shell 5 holds only 8 of its 50-electron capacity (5s² 5p⁶; no 5d or 5f electrons). Shell 6 carries just the 2 outermost 6s electrons.

The Xenon Core — [Xe]

The first 54 electrons of ytterbium match the complete electron configuration of xenon (Z=54):

[Xe] = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶

The remaining 16 electrons — 4f¹⁴ 6s² — govern ytterbium's chemistry, optical properties, and oxidation states.

Orbital Box Diagram — Valence Region

The xenon core (1s² through 5p⁶, 54 electrons) is shown in compact form. The valence subshells 4f and 6s are shown in detail.

[Xe]

core: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶

54 electrons, all paired — xenon configuration

14 electrons — all 7 orbitals doubly occupied (completely filled, all paired)

2 electrons (paired) — outermost shell

Each box = one orbital. Opposing arrows = paired electrons (+½ and −½ spin). Colored border = filled subshell.

Ytterbium has 0 unpaired electrons — all 4f¹⁴ orbitals are doubly occupied and the 6s² electrons are paired. This makes ytterbium diamagnetic, unusual among lanthanides.

Quantum Numbers — Valence Electrons (post-[Xe])

Electron #	n	l	mₗ	mₛ	Subshell
55	4	3	-3	+½	4f
56	4	3	-2	+½	4f
57	4	3	-1	+½	4f
58	4	3	0	+½	4f
59	4	3	+1	+½	4f
60	4	3	+2	+½	4f
61	4	3	+3	+½	4f
62	4	3	-3	−½	4f
63	4	3	-2	−½	4f
64	4	3	-1	−½	4f
65	4	3	0	−½	4f
66	4	3	+1	−½	4f
67	4	3	+2	−½	4f
68	4	3	+3	−½	4f
69	6	0	0	+½	6s
70	6	0	0	−½	6s

Electrons 1–54 fill the xenon core (not shown). n = principal quantum number; l = azimuthal (3→f); mₗ = magnetic (−3 to +3 for f); mₛ = spin. The 4f subshell fills all seven orbitals first with spin +½ (Hund's rule), then pairs each with −½, completing 4f¹⁴. Both 6s electrons are paired.

Summary

Reference tool for ytterbium's electron configuration ([Xe] 4f¹⁴ 6s²), orbital diagram, its completely filled 4f subshell, and properties including fiber laser and atomic clock uses.

How it works

The Aufbau principle fills orbitals from lowest to highest energy, placing the xenon core (1s² through 5p⁶, 54 electrons) first.
After the xenon core, the 4f subshell fills across the lanthanide series; at ytterbium (Z=70) all fourteen 4f orbitals are occupied — 4f¹⁴.
A completely filled 4f¹⁴ subshell has all electrons paired, giving ytterbium zero unpaired electrons and a diamagnetic ground state.
The outermost electrons are 6s², making ytterbium's valence shell resemble an alkaline-earth element (like barium) more than a typical lanthanide.
Loss of the 6s² electrons gives Yb²⁺ ([Xe] 4f¹⁴), a stable closed-shell ion — this is why Yb²⁺ is more accessible than for most lanthanides.
Loss of one additional 4f electron gives the more common Yb³⁺ ([Xe] 4f¹³), the dominant oxidation state in coordination chemistry and materials.

Use cases

Quick reference for chemistry homework or exam review on lanthanide electron configurations.
Understand why ytterbium shows an accessible +2 state due to its closed 4f¹⁴ shell stability.
Visualize how the 4f subshell reaches full occupancy at the end of the lanthanide series.
Explain why Yb-doped fiber lasers operate at 1030 nm — the 4f¹³ ↔ 4f¹⁴ electronic transitions.
Compare ytterbium to adjacent lanthanides (thulium, lutetium) to see 4f-filling completion.
Teaching aid for closed-shell stability and its effect on oxidation states in f-block chemistry.
Understand ytterbium's role in optical lattice atomic clocks based on its sharp 4f transitions.

Frequently Asked Questions

Last updated: 2026-07-27 · Reviewed by Nham Vu