Cadmium (Cd)
Cadmium is element 48, a transition metal in period 5, group 12 of the periodic table. At room temperature it is a solid.
Electron configuration [Kr] 4d10 5s2
Electrons per shell 2, 8, 18, 18, 2
Cadmium data
| Atomic number | 48 |
|---|---|
| Symbol | Cd |
| Atomic mass | 112.411 u |
| Category | Transition metal |
| Group | 12 |
| Period | 5 |
| Block | d |
| State at 25 °C | solid |
| Melting point | 594 K (320.9 °C) |
| Boiling point | 1040 K (766.9 °C) |
| Density | 8.65 g/cm³ |
| Electronegativity (Pauling) | 1.69 |
| Atomic radius | 148 pm |
| 1st ionization energy | 868 kJ/mol |
| Electron affinity | 0 kJ/mol |
| Oxidation states | +2 |
| Common ion charge | 2+ |
| Discovered | 1817 |
Orbital diagram
Each box is one orbital holding up to two electrons of opposite spin. Following Hund’s rule, electrons spread out singly across a subshell before pairing.
Work through cadmium’s configuration and its ions →
Where cadmium sits
Cadmium belongs to the transition metals. Its Pauling electronegativity of 1.69 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Cadmium FAQ
What is the electron configuration of cadmium?
Cadmium (Z = 48) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2. In noble-gas shorthand that is [Kr] 4d10 5s2.
How many valence electrons does cadmium have?
12 (2 outer s + 10 d electrons; 2 in the outermost shell).
What is the atomic mass of cadmium?
The standard atomic weight of cadmium is 112.411 u, so one mole weighs 112.411 g.
Is cadmium a metal?
Yes. Cadmium is a transition metal.
What is the charge of a cadmium ion?
Cadmium most commonly forms Cd2+.