58
Ce
Cerium
140.1161
Cerium
LANTHANIDE
Bohr Model: Electrons arranged in energy shells around the nucleus.
Cerium is a chemical element with symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet Ceres (itself named after the Roman goddess of agriculture).
Quick Facts
Atomic Number 58
Period 6
Group 4
Phase Solid
Appearance silvery white
About Lanthanides
Lanthanides are shiny metallic elements with atomic numbers 57–71. They are often called 'rare-earth elements' and are used in magnets and lasers.
History
Discovered By Martin Heinrich Klaproth
Named By Unknown
Physical Properties
Atomic Mass 140.1161
Density 6.77 g/L
Molar Heat 26.94 J/(mol·K)
Phase Transition (Melting & Boiling Points)
Cerium melts at 1068 K and boils at 3716 K.
Atomic Properties
Electron Config [Xe] 4f1 5d1 6s2
Electronegativity 1.12
Electron Affinity 55 kJ/mol
Ionization Energy 534.4 kJ/mol
Orbital Filling Diagram
This diagram visualizes electron configuration according to the Aufbau principle and Hund's rule.
Boxes represent orbitals (s, p, d, f), while arrows indicate electrons with spin up or down.
Electrons fill lower energy levels first and occupy orbitals singly before pairing.
Photograph
External Resources
Study Guide
Atomic Number
The number of protons in the nucleus, which defines the element.
Atomic Mass
The average mass of an atom, including protons and neutrons.
Electronegativity
A measure of how strongly an atom attracts electrons in a bond.
Ionization Energy
The energy required to remove an electron from an atom.
Electron Config
The arrangement of electrons in the atom's energy shells.