Element 48 · Transition metal
Cadmium (Cd) — Element 48
Latin cadmia — calamine
Cadmium (Cd) is a transition metal in Period 5, Group 12 of the periodic table with atomic number 48, standard atomic weight 112.41 u, and ground-state electron configuration [Kr] 4d¹⁰ 5s². At standard temperature and pressure it is classified as a solid with 12 valence electrons and common oxidation states +2.
Batteries, pigments, plating
What are the atomic properties and physical constants of Cadmium?
Reference constants compiled from IUPAC standard atomic weights, the NIST Atomic Spectra Database, and the CRC Handbook.
- Atomic number (Z)
- 48
- Standard atomic mass
- 112.41 u
- Chemical family
- Transition metal
- Ground-state configuration
- [Kr] 4d¹⁰ 5s²
- Electrons per shell
- 2, 8, 18, 18, 2
- Valence electrons
- 12
- Common ion charges / oxidation states
- +2
- Phase at STP
- Solid
- Pauling electronegativity
- 1.69 Pauling
- First ionization energy
- 868 kJ/mol
- Atomic radius
- 161 pm
- Melting point
- 321 °C
- Boiling point
- 767 °C
- Discovery year
- 1817
- Table coordinate
- Period 5, Group 12
- Radioactivity
- Has stable isotope(s)
How are electrons arranged across Cadmium’s shells?
A neutral Cadmium atom contains 48 electrons distributed across 5 occupied principal energy shells ([Kr] 4d¹⁰ 5s²). The table below compares Cadmium’s shell occupancy against each shell’s theoretical 2n² capacity.
| Principal Shell (n) | Spectroscopic Letter | Electrons in Cd | Max Shell Capacity (2n²) |
|---|---|---|---|
| n = 1 | K | 2 e⁻ | 2 e⁻ |
| n = 2 | L | 8 e⁻ | 8 e⁻ |
| n = 3 | M | 18 e⁻ | 18 e⁻ |
| n = 4 | N | 18 e⁻ | 32 e⁻ |
| n = 5 | O | 2 e⁻ | 50 e⁻ |
Frequently Asked Questions about Cadmium (Cd)
What is the atomic mass and atomic number of Cadmium (Cd)?
Cadmium (Cd) has atomic number Z = 48 (48 protons in its nucleus) and an IUPAC standard atomic weight of 112.41 u. It sits in Period 5, Group 12 and is classified as a transition metal.
What is the ground-state electron configuration of Cadmium?
The neutral ground-state electron configuration of Cadmium (Z = 48) is [Kr] 4d¹⁰ 5s². Across its 5 occupied principal shells (n = 1 to n = 5), the electrons per shell are 2, 8, 18, 18, 2, with 12 valence electrons participating in bonding.
What are the common ion charges and electronegativity of Cadmium?
Cadmium commonly forms +2 oxidation states or ion charges in compounds. Its Pauling electronegativity is 1.69 and its first ionization energy is 868 kJ/mol.
When was Cadmium discovered and what is it used for?
Cadmium was discovered in 1817 (Latin cadmia — calamine). Batteries, pigments, plating
How does Cadmium compare to neighboring elements?
Other transition metal elements: