Zirconium (symbol Zr, atomic number 40) is a corrosion-resistant metal used to clad nuclear fuel rods. It is classified as a transition metal and sits in group 4, period 5 of the periodic table.
Overview
Zirconium is the chemical element with atomic number 40 and the symbol Zr. With a standard atomic weight of 91.224, it is a transition metal. In the periodic table it occupies group 4 and period 5, and under standard conditions it is normally a solid. Zirconium is a corrosion-resistant metal used to clad nuclear fuel rods.
Atomic structure
An atom of Zirconium has 40 protons in its nucleus and, when neutral, 40 electrons arranged in the configuration [Kr] 4d2 5s2. Its standard atomic weight of 91.224 reflects the natural mix of its stable isotopes.
Discovery and place in the table
Zirconium was discovered in 1789 by Martin Heinrich Klaproth. It follows Yttrium (Y) and precedes Niobium (Nb) in order of atomic number.
| Atomic number | 40 |
|---|---|
| Symbol | Zr |
| Atomic mass | 91.224 |
| Category | Transition metal |
| Group | 4 |
| Period | 5 |
| Electron configuration | [Kr] 4d2 5s2 |
| Phase at STP | Solid |
| Discovered | 1789 (Martin Heinrich Klaproth) |