Cerium (Ce)

Element 58 · lanthanide · group 3, period 6

• 58 protons
• 2/3 valence e−
• +3
• f-block

Properties

Electron configuration of cerium

Orbitals fill from the lowest energy upward. Writing that out for cerium gives 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹ 5s² 5p⁶ 5d¹ 6s², which is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f1 5s2 5p6 5d1 6s2 in plain text.

Everything up to Xe is the same as in that noble gas, so it is usually abbreviated to [Xe] 4f¹ 5d¹ 6s². The part outside the bracket is what does the chemistry.

Cerium ion charge

Cerium commonly forms ions with a charge of +3.

Common questions

How many valence electrons does cerium have?

There is no single agreed answer for cerium. The f-block elements draw on three subshells, so a single valence count is not meaningful for them. Check which convention your course uses before answering.

What is the electron configuration of cerium?

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f1 5s2 5p6 5d1 6s2, or [Xe] 4f1 5d1 6s2 written from the previous noble gas. Orbitals fill lowest energy first, but cerium is one of the elements that breaks that order - a half-filled or filled d subshell is stable enough to be worth borrowing an s electron for.

What is the charge of cerium?

Cerium commonly forms ions with a charge of +3. Transition metals have several accessible oxidation states, which is why more than one charge is listed.

How many protons, electrons and neutrons does cerium have?

A neutral cerium atom has 58 protons and 58 electrons. Its standard atomic weight is 140.12, so the most common isotope has about 82 neutrons.

Nearby elements

• Lanthanum (La)above it in group 3
• Praseodymium (Pr)below it in group 3
• Scandium (Sc)same group, same valence count
• Yttrium (Y)same group, same valence count
• Neodymium (Nd)same group, same valence count
• Promethium (Pm)same group, same valence count

See the ionic charge of every element →