Cadmium (Cd): Electron Configuration, Properties and Uses
Cadmium (Cd): Electron Configuration, Properties and Uses
Electron configuration [Kr] 5s2 4d10 · group 12 · period 5 · Ar 112.41
Cadmium data
- Atomic number
- 48
- Relative atomic mass
- 112.41
- Group
- 12
- Period
- 5
- Block
- d
- Category
- Transition metal
- Electron configuration
- [Kr] 5s2 4d10
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10
- Electrons per shell
- 2, 8, 18, 18, 2 (K L M N O)
- Valence electrons
- 12
- Electronegativity (Pauling)
- 1.69
- First ionisation energy
- 8.994 eV
- Atomic radius (van der Waals)
- 158 pm
- State at room temperature
- Solid
- Melting point
- 321 °C
- Boiling point
- 767 °C
- Density
- 8.69 g/cm³
- Common oxidation states
- +2
- Discovered
- 1817
Source: PubChem (NIH, accessed 13 Nov 2026); atomic mass: IUPAC standard atomic weight.
Electron shell diagram
K 2 · L 8 · M 18 · N 18 · O 2
Orbital diagram (outer electrons)
About cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. It is a transition metal in group 12, period 5, d-block. Cadmium was first discovered in 1817. Cadmium is a solid at room temperature, melting at 321 °C and boiling at 767 °C.
Cadmium electron configuration
The electron configuration of cadmium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10, or in short [Kr] 5s2 4d10. Its electrons occupy 5 shells: K = 2, L = 8, M = 18, N = 18, O = 2. For transition metals, valence electrons are counted from the 5s and 4d subshells: 2 + 10 = 12, matching group 12. When it forms cations, electrons leave the outermost subshell first: Cd2+ = [Kr] 4d10.
Filling order: 1s2(2) → 2s2(4) → 2p6(10) → 3s2(12) → 3p6(18) → 4s2(20) → 3d10(30) → 4p6(36) → 5s2(38) → 4d10(48)
Uses of cadmium
The main uses of cadmium include NiCd batteries, yellow-red pigments, CdSe quantum dots and CdTe solar cells. For research and analysis you can browse cadmium compounds in the AMI Scientific catalogue.
Safety
Cadmium is toxic, carcinogenic and accumulates in the kidneys. Always read the safety data sheet (SDS) before working with a chemical.
Other elements in group 12
Frequently asked questions
What is the electron configuration of cadmium?
The electron configuration of cadmium (Cd, atomic number 48) is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10, or [Kr] 5s2 4d10 in short. By shell: 2, 8, 18, 18, 2.
How many valence electrons does cadmium have?
Cadmium has 12 valence electrons.
Which group and period is cadmium in?
Cadmium is in group 12, period 5, d-block.
What is the atomic mass of cadmium?
The relative atomic mass of cadmium is 112.41. Use it to calculate molar mass with the molar mass calculator.
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