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Cd

Cadmium

Cadmium (Cd) is a transition metal with atomic number 48 and an atomic mass of 112.41. Its electron configuration is [Kr] 4d10 5s2.

Cadmium key data

Symbol Cd
Atomic number 48
Atomic mass (standard atomic weight) 112.41
Molar mass 112.41 g/mol
Protons 48
Neutrons (most abundant isotope, cadmium-114) 66
Electrons (neutral atom) 48
Category Transition metal
Period 5
Group 12
Block d-block
Noble gas notation [Kr] 4d10 5s2
Full electron configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2
Electrons per shell 2, 8, 18, 18, 2

Atomic mass: IUPAC CIAAW abridged standard atomic weights, 2024. Most abundant isotope: NIST Atomic Weights and Isotopic Compositions.

The values are facts and free to use; this page’s selection and presentation are © 2026 ScienceQuest.

Measured properties of cadmium

From PubChem, the US National Institutes of Health. Public domain. PubChem’s periodic table gives no value for the rows not shown.

Melting point 594.22 K (321.07 °C), 73rd of 103 by melting point
Boiling point 1040 K (766.85 °C), 72nd of 93 by boiling point
Density 8.69 g/cm³, 36th of 96 by density
State at room temperature Solid
Electronegativity 1.69 (Pauling), 44th of 95 by electronegativity
Van der Waals radius 158 pm, 90th of 99 by atomic radius
First ionisation energy 8.994 eV (867.8 kJ/mol), 25th of 102 by first ionisation energy
Common oxidation states +2
Discovered 1817

Each rank counts down from the highest value, among the elements PubChem’s table gives one for, and links to that property ranked across the whole table. All of them are collected under periodic trends.

Cadmium electron configuration

The full electron configuration of cadmium is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2. With the noble-gas core collapsed it is [Kr] 4d10 5s2, and the outermost subshell is 5s2.

Bohr model of cadmium (Cd): a nucleus and five shells holding 2, 8, 18, 18 and 2 electrons from the inside out.
Bohr model of cadmium (Cd). Image © ScienceQuest, CC BY 4.0: free to reuse with credit to ScienceQuest and a link to this page, as the image licence explains.
Orbital box diagram of cadmium (Cd), [Kr] 4d10 5s2, with the krypton core drawn as one bar: one box per orbital, filled by Hund’s rule, showing every orbital drawn holds a pair of electrons.
Orbital diagram of cadmium (Cd). Image © ScienceQuest, CC BY 4.0: free to reuse with credit to ScienceQuest and a link to this page, as the image licence explains.

Why group and block follow from this is set out in how the periodic table maps electron configuration, and the electron configuration of every element is listed on one page.

Mass of one cadmium atom

A molar mass is grams per mole, so dividing by the Avogadro constant gives the mass of a single atom, or for an element with more than one natural isotope the average mass of its atoms, and the reciprocal gives how many atoms sit in a gram.

Mass of one atom

  1. one atom = 112.41 / (6.02214076 × 10²³)
  2. = 1.8666 × 10⁻²² g

Atoms in one gram

  1. atoms per gram = 6.02214076 × 10²³ / 112.41
  2. = 5.3573 × 10²¹ atoms

Cadmium on the periodic table

Cadmium is in period 5, group 12, in the d-block.

The other elements of group 12 are zinc, mercury and copernicium.

The rest of period 5

Work with cadmium