Cerium (Ce)

Cerium properties

Atomic number

58

Atomic mass

140.12 u

Category

Lanthanide

Group

—

Period

6

Block

f-block

State at room temp.

Solid

Electronegativity

1.12

Melting point

1,068 K (794.8 °C)

Boiling point

3,716 K (3,442.8 °C)

Density

6.77 g/cm³

Valence electrons

2

Common charges

+3, +4

Oxidation states

+4, +3

Atomic radius

235 pm

Ionization energy

5.539 eV

Electron affinity

0.5 eV

Radioactive

No, has stable isotopes

Discovered

1803

Cerium electron configuration

The electron configuration of Cerium (Ce) is [Xe] 4f1 5d1 6s2. Its 58 electrons are arranged in shells as 2, 8, 18, 19, 9, 2.

Protons, neutrons and electrons in Cerium

A neutral Cerium atom has 58 protons and 58 electrons. Most Cerium atoms have about 82 neutrons: the atomic mass rounded to 140, minus the atomic number 58.

Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass

How many valence electrons does Cerium have?

2

Cerium has 2 valence electrons in its outermost shell. As an f-block element, its 4f or 5f electrons can also take part in bonding.

See every element: Periodic table with valence electrons

Cerium orbital diagram

Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations

Molar mass of Cerium

140.12 g/mol

One mole of Cerium atoms (6.022 × 10²³ atoms) has a mass of 140.12 grams. Use this value to convert between grams and moles.

Cerium facts

• Cerium is the most abundant of the rare earth elements in Earth's crust.
• It is named after the dwarf planet Ceres, which had been discovered just two years earlier, in 1801.
• Cerium (Ce) has atomic number 58 and is a solid at room temperature. It was discovered in 1803.

Position in the periodic table

Cerium is element 58, in period 6 of the periodic table. It is one of the Lanthanides in the f-block, shown in the rows below the main table.

All lanthanides

Uses of Cerium

Cerium oxide is the standard polishing powder for glass, used to finish lenses, mirrors, and phone screens. Cerium also helps catalytic converters store and release oxygen, and it is added to glass to block ultraviolet light. Mixed with iron in the alloy ferrocerium, it makes the sparking 'flints' in cigarette lighters and fire starters.

Who discovered Cerium?

Cerium was discovered in 1803 by Jöns Jacob Berzelius and Wilhelm Hisinger in Sweden, and independently by Martin Heinrich Klaproth in Germany, in the mineral now called cerite. The pure metal was not isolated until 1875.

Where does the name come from?

Cerium is named after Ceres, a dwarf planet in the asteroid belt discovered in 1801, two years before the element. Ceres itself honors the Roman goddess of agriculture.

Discovery timeline