---
title: "Palladium (Pd) — element 46"
description: "Palladium is element 46, symbol Pd, atomic weight 106.42. Configuration, properties, uses and neighbours."
url: https://atoneplace.net/element/palladium/
site: "At One Place"
---

# Palladium (Pd)

**Palladium — element 46: Pd**

106.42 u · Transition metal · period 5, group 10

Palladium absorbs up to about 900 times its own volume of hydrogen at room temperature, swelling as the gas dissolves into the metal lattice — a property discovered by Thomas Graham in 1866 and still used to purify hydrogen, since nothing else diffuses through. It is the only element with no electrons in its outermost s shell in the ground state: [Kr] 4d¹⁰, with the 5s subshell completely empty, which no other atom manages. The 2010 Nobel Prize in Chemistry went to palladium-catalysed cross-coupling, the reaction family behind a large share of modern pharmaceuticals.

## Properties

- **Atomic number:** 46
- **Symbol:** Pd
- **Standard atomic weight:** 106.42 u
- **Category:** Transition metal
- **Group:** 10
- **Period:** 5
- **Block:** d-block
- **Electron configuration:** [Kr] 4d¹⁰
- **Electrons per shell:** 2, 8, 18, 18
- **Melting point:** 1,828.05 K — 1554.9 °C — 2830.8 °F
- **Boiling point:** 3,236 K — 2962.8 °C — 5365.1 °F
- **Density:** 12 g/cm³
- **Electronegativity:** 2.2 (Pauling)
- **Oxidation states:** +2, +4
- **Discovered:** 1802 by William Hyde Wollaston

## Electron configuration

- **Full:** 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 4d¹⁰
- **Noble gas shorthand:** [Kr] 4d¹⁰
- **Shells:** K: 2 · L: 8 · M: 18 · N: 18

## What it is used for

- Catalytic converters on petrol engines
- Multilayer ceramic capacitors, in enormous numbers
- Palladium-catalysed cross-coupling in drug manufacture
- Hydrogen purification membranes
- White gold alloys and dental crowns

> The most striking configuration anomaly in the table: [Kr] 4d¹⁰, with an empty 5s subshell, rather than the predicted 5s² 4d⁸. Palladium is the only element whose ground state has no electrons in the outermost s orbital.

## Neighbours in the table

| Z | Element | Symbol | Mass |
| --- | --- | --- | --- |
| 44 | Ruthenium | Ru | 101.07 |
| 45 | Rhodium | Rh | 102.91 |
| 46 | Palladium ← | Pd | 106.42 |
| 47 | Silver | Ag | 107.87 |
| 48 | Cadmium | Cd | 112.41 |

## Group 10

Elements in the same group share their outer electron count, which is why they behave similarly in reactions. Palladium sits in group 10 with nickel, platinum, darmstadtium.

## Common questions

### What is the atomic number of palladium?

46. That is the number of protons in its nucleus, which is what defines the element.

### What is the symbol for palladium?

Pd.

### What is the electron configuration of palladium?

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 4d¹⁰, or [Kr] 4d¹⁰ in noble-gas shorthand.

### What is the melting point of palladium?

1,828.05 K — 1554.9 °C — 2830.8 °F

## Related pages

- [Ruthenium (Ru)](https://atoneplace.net/element/ruthenium/)
- [Rhodium (Rh)](https://atoneplace.net/element/rhodium/)
- [Silver (Ag)](https://atoneplace.net/element/silver/)
- [Cadmium (Cd)](https://atoneplace.net/element/cadmium/)
- [Nickel (Ni)](https://atoneplace.net/element/nickel/)
- [Platinum (Pt)](https://atoneplace.net/element/platinum/)
- [Darmstadtium (Ds)](https://atoneplace.net/element/darmstadtium/)

## Sources

- Official vendor product documentation — At One Place (/about/)