Cadmium (Cd)
Transition metal · d-block · period 5 · group 12
Soft, bluish-white metal that can be cut with a knife.
Cadmium (symbol Cd) is chemical element number 48, a transition metal in group 12, period 5 of the periodic table. Its standard atomic weight is 112.41 and its electron configuration is [Kr] 4d10 5s2. At room temperature it is a solid. Toxic and cumulative — it damages the kidneys and bones over time.
Properties
| Atomic number | 48 |
|---|---|
| Atomic mass | 112.41 |
| Category | Transition metal |
| Block | d-block |
| Group · Period | 12 · 5 |
| Electron configuration | [Kr] 4d10 5s2 |
| Electrons per shell | 2, 8, 18, 18, 2 |
| State at 25 °C | solid |
| Melting point | 594.22 K |
| Boiling point | 1040 K |
| Density | 8.65 g/cm³ |
| Electronegativity (Pauling) | 1.69 |
| Radioactive | No |
| Origin | primordial |
| Discovered | 1817 · Stromeyer & Hermann |
Key facts about Cadmium
- Toxic and cumulative — it damages the kidneys and bones over time.
- Gave paints their vivid 'cadmium yellow', 'orange' and 'red', now largely phased out.
- The rechargeable NiCd battery uses a cadmium electrode.
- Absorbs neutrons well, so cadmium rods can shut down a nuclear reactor.
What Cadmium is used for
Rechargeable batteries, corrosion-resistant plating, reactor control rods, pigments (declining), solder.
Where it sits in the periodic table
Cadmium is in group 12, period 5, of the d-block. Its electron configuration [Kr] 4d10 5s2 means its outermost shell holds 2 electrons, which is what places it here and explains much of its chemistry. See Cadmium on the interactive table →
Cadmium — frequently asked questions
What is Cadmium used for?
Rechargeable batteries, corrosion-resistant plating, reactor control rods, pigments (declining), solder.
Is Cadmium radioactive?
No. Cadmium has at least one stable isotope and is not radioactive.
What is the electron configuration of Cadmium?
Cadmium has the electron configuration [Kr] 4d10 5s2, which is 2, 8, 18, 18, 2 electrons per shell.
What group and period is Cadmium in?
Cadmium is in group 12, period 5, in the d-block. Its outer shell holds 2 electrons.
Who discovered Cadmium?
Cadmium was discovered in 1817 by Stromeyer & Hermann.