What is the electron configuration of palladium?

Palladium (Pd, Z=46) has the ground-state electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰, or in noble-gas shorthand [Kr] 4d¹⁰. This is anomalous — the Aufbau principle would predict [Kr] 4d⁸ 5s².

Why is palladium's electron configuration anomalous?

A completely filled 4d subshell (4d¹⁰) is especially stable because all five d orbitals are fully paired, maximizing exchange-energy gain and minimizing electron-electron repulsion. This stabilization is large enough that both predicted 5s electrons shift into 4d, leaving the 5s orbital empty.

What makes palladium unique among 4d transition metals?

Palladium is the only element in the 4d series with a d¹⁰ s⁰ ground state. All other anomalous 4d transition metals (like molybdenum, [Kr] 4d⁵ 5s¹) still retain at least one s electron. Palladium's 5s orbital is completely empty.

What is the noble-gas shorthand for palladium?

The condensed notation is [Kr] 4d¹⁰, where [Kr] represents the filled krypton core (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶, Z=36).

How many valence electrons does palladium have?

Palladium has 10 valence electrons, all in the 4d subshell. Because the 5s is empty, palladium's chemistry is dominated by its d electrons, explaining its common +2 and +4 oxidation states.

What are palladium's common oxidation states?

Palladium most commonly exhibits +2 (e.g., PdCl₂, Pd(NH₃)₂Cl₂) and +4 (e.g., PdF₄, PdCl₄²⁻). The +2 state is dominant in aqueous chemistry and catalysis. A +0 state appears in organometallic complexes like Pd(PPh₃)₄.

What block and period is palladium in?

Palladium is in Period 5, Group 10, and belongs to the d-block (transition metals). It sits between rhodium (Z=45) and silver (Z=47) in Period 5, and directly below nickel (Z=28) and above platinum (Z=78) in Group 10.

What is palladium used for?

Palladium is widely used in catalytic converters for vehicle exhaust, in hydrogen purification (palladium absorbs hydrogen readily), in Pd-catalyzed cross-coupling reactions (Suzuki, Heck, Negishi) central to pharmaceutical synthesis, and in jewelry alloys such as white gold.

Palladium Electron Configuration

Name: Palladium Electron Configuration
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Author: Nham Vu

Palladium (Pd, Z=46) has the unique electron configuration [Kr] 4d¹⁰ — a completely filled d subshell with an empty 5s orbital, making it the only 4d transition metal with a d¹⁰ s⁰ ground state.

Z = 46 Pd Palladium

Palladium — Electron Configuration

Atomic number 46 · Transition metal · Period 5, Group 10 · d-block

[Kr] 4d¹⁰ d¹⁰ s⁰ anomaly 46 electrons 10 valence e⁻ 5s empty

Aufbau Exception: d¹⁰ s⁰

The Aufbau principle predicts [Kr] 4d⁸ 5s² for palladium. The actual ground state is [Kr] 4d¹⁰ — both predicted 5s electrons shift into 4d, leaving the 5s completely empty. Palladium is the only 4d transition metal with this d¹⁰ s⁰ ground state.

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	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
5s	s orbital, shell n=5 (empty — anomalous)	0	2	5s⁰
Total		46

Full Configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰

All subshells written explicitly. Note: 5s⁰ is omitted.

Noble-Gas Shorthand

[Kr] 4d¹⁰

[Kr] = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶.

Aufbau Prediction (wrong)

[Kr] 4d⁸ 5s²

Aufbau fills 5s before 4d, but d¹⁰ is more stable.

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 18 / 32 electrons (56%)

Shell 5 (n=5) — 5s⁰ (empty) 0 / 50 electrons (0%)

Shell 5 is completely empty in palladium's ground state — the anomalous d¹⁰ configuration leaves 5s unoccupied. The next element, silver (Z=47), adds one electron into 5s: [Kr] 4d¹⁰ 5s¹.

Group 10 Configurations: Ni, Pd, Pt

Element	Z	Actual Configuration	Anomaly?
Nickel (Ni)	28	[Ar] 3d⁸ 4s²	No (follows Aufbau)
Palladium (Pd)	46	[Kr] 4d¹⁰	Yes — d¹⁰ s⁰, unique
Platinum (Pt)	78	[Xe] 4f¹⁴ 5d⁹ 6s¹	Yes — one 6s electron, d⁹ s¹

Palladium is the only Group 10 element — and the only 4d transition metal overall — that completely empties its outermost s orbital in the ground state.

Orbital Box Diagram — [Kr] core + 4d¹⁰

The [Kr] core (1s² through 4p⁶, 36 electrons) is shown collapsed. The valence region shows the anomalous 4d¹⁰ with a completely empty 5s orbital.

[Kr] core

1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ — 36 electrons, fully filled

10 electrons across 5 orbitals — fully filled (4d¹⁰)

empty

0 electrons — anomalously empty in ground state

Every 4d orbital in palladium holds two paired electrons (opposite spins). The 5s orbital, which Aufbau predicts should hold 2 electrons, is empty. Palladium is diamagnetic: all electrons are paired, so it is not attracted to a magnetic field.

Quantum Numbers — 4d Valence Electrons (e⁻ 37–46)

e⁻ #	n	l	mₗ	mₛ	Subshell
37	4	2	-2	+½	4d
38	4	2	-2	−½	4d
39	4	2	-1	+½	4d
40	4	2	-1	−½	4d
41	4	2	0	+½	4d
42	4	2	0	−½	4d
43	4	2	1	+½	4d
44	4	2	1	−½	4d
45	4	2	2	+½	4d
46	4	2	2	−½	4d

n = principal quantum number; l = azimuthal (l=2 → d); mₗ = magnetic (−2 to +2 for d orbitals); mₛ = spin. Electrons 1–36 fill the [Kr] core identically to krypton.

Summary

How it works

The Aufbau principle predicts [Kr] 4d⁸ 5s² for palladium — 8 electrons in 4d and 2 in 5s.
Instead, both 5s electrons shift into 4d, yielding [Kr] 4d¹⁰ with a completely filled d subshell and an empty 5s.
A fully filled d subshell (10 electrons across five orbitals) achieves maximum exchange-energy stabilization.
The energy gain from maximizing electron pairing in 4d outweighs the cost of vacating 5s.
Palladium is unique among 4d metals: it is the only one in this series with a d¹⁰ s⁰ ground state.
Nickel (Z=28) shows a related trend one period above but retains two 4s electrons rather than fully emptying them.

Use cases

Verify palladium's actual ground-state configuration vs. the Aufbau prediction.
Understand why [Kr] 4d¹⁰ is uniquely stable compared with [Kr] 4d⁸ 5s².
Study the d¹⁰ s⁰ anomaly and compare it with other anomalous transition metals.
Review palladium's oxidation states (+2, +4) and how d¹⁰ relates to Pd chemistry.
Use the quantum-number table for all 46 electrons in exam preparation.
Teaching aid for inorganic chemistry courses on d-block electronic structure exceptions.
Quick reference for periodic trends across Period 5 transition metals.
Compare Pd with Pt (Period 6) and Ni (Period 4) in the same Group 10.

Frequently Asked Questions

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