Cerium (Ce): Electron Configuration, Properties and Uses
Cerium (Ce): Electron Configuration, Properties and Uses
Electron configuration [Xe] 6s2 4f1 5d1 · f-block, lanthanide series · period 6 · Ar 140.12
Cerium data
- Atomic number
- 58
- Relative atomic mass
- 140.12
- Group
- – (lanthanide series)
- Period
- 6
- Block
- f
- Category
- Lanthanide
- Electron configuration
- [Xe] 6s2 4f1 5d1
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f1 5d1
- Electrons per shell
- 2, 8, 18, 19, 9, 2 (K L M N O P)
- Valence electrons
- 2 (in the outer shell)
- Electronegativity (Pauling)
- 1.12
- First ionisation energy
- 5.539 eV
- Atomic radius (van der Waals)
- 235 pm
- State at room temperature
- Solid
- Melting point
- 798 °C
- Boiling point
- 3424 °C
- Density
- 6.77 g/cm³
- Common oxidation states
- +4, +3
- Discovered
- 1803
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 18 · N 19 · O 9 · P 2
Orbital diagram (outer electrons)
About cerium
With atomic number 58, cerium (Ce) has 58 protons in its nucleus and 58 electrons as a neutral atom. It belongs to the lanthanide series in period 6 (f-block), usually shown below the main table. Cerium was first discovered in 1803. Cerium is a solid at room temperature, melting at 798 °C and boiling at 3424 °C.
Cerium electron configuration
The electron configuration of cerium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f1 5d1, or in short [Xe] 6s2 4f1 5d1. Its electrons occupy 6 shells: K = 2, L = 8, M = 18, N = 19, O = 9, P = 2. As a lanthanide, cerium fills the 4f subshell. Its outer 6s subshell holds 2 electrons; valence electrons for this series are not assigned by the usual group rule. This is an exception to the Aufbau rule: the usual filling order predicts [Xe] 6s2 4f2, but the 4f and 5d subshells are so close in energy that electrons occupy 5d. When it forms cations, electrons leave the outermost subshell first: Ce3+ = [Xe] 4f1.
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) → 4f1(57) → 5d1(58)
Uses of cerium
In industry and the laboratory, cerium turns up in many places, for example glass polishing powder (cerium oxide), catalytic converters and lighter flints (mischmetal). For research and analysis you can browse cerium compounds in the AMI Scientific catalogue.
Safety
Bulk cerium has low toxicity. The main hazards are its dust and salts, so always check the SDS of the compound you use. Always read the safety data sheet (SDS) before working with a chemical.
Other lanthanides
Frequently asked questions
What is the electron configuration of cerium?
The electron configuration of cerium (Ce, atomic number 58) is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f1 5d1, or [Xe] 6s2 4f1 5d1 in short. By shell: 2, 8, 18, 19, 9, 2.
How many valence electrons does cerium have?
Cerium has 2 electrons in its outer shell. For lanthanides and actinides, valence electrons are not assigned by the usual group rule.
Which group and period is cerium in?
Cerium is in the lanthanide series, period 6, f-block.
What is the atomic mass of cerium?
The relative atomic mass of cerium is 140.12. Use it to calculate molar mass with the molar mass calculator.
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