Cadmium (symbol Cd, atomic number 48) is a toxic metal used in pigments and rechargeable NiCd batteries. It is classified as a transition metal and sits in group 12, period 5 of the periodic table.
Overview
Cadmium is the chemical element with atomic number 48 and the symbol Cd. With a standard atomic weight of 112.41, it is a transition metal. In the periodic table it occupies group 12 and period 5, and under standard conditions it is normally a solid. Cadmium is a toxic metal used in pigments and rechargeable NiCd batteries.
Atomic structure
An atom of Cadmium has 48 protons in its nucleus and, when neutral, 48 electrons arranged in the configuration [Kr] 4d10 5s2. Its standard atomic weight of 112.41 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Cadmium was discovered in 1817 by Karl Samuel Leberecht Hermann, Friedrich Stromeyer. It follows Silver (Ag) and precedes Indium (In) in order of atomic number.
| Atomic number | 48 |
|---|---|
| Symbol | Cd |
| Atomic mass | 112.41 |
| Category | Transition metal |
| Group | 12 |
| Period | 5 |
| Electron configuration | [Kr] 4d10 5s2 |
| Phase at STP | Solid |
| Discovered | 1817 (Karl Samuel Leberecht Hermann, Friedrich Stromeyer) |