4091.224ZrZirconium
Zirconium (Zr) — element 40transition metal · group 4, period 5
Zirconium is a chemical element with the symbol Zr and atomic number 40. It is a transition metal in group 4, period 5 of the periodic table (the d-block), with a standard atomic mass of 91.224 u. At room temperature (25 °C) zirconium is a solid.
💡 Known for: Resists corrosion and absorbs few neutrons, so it clads nuclear fuel rods; cubic zirconia is a diamond simulant.
# Zirconium properties
| Symbol | Zr |
|---|---|
| Atomic number | 40 |
| Atomic mass | 91.224 u |
| Category | transition metal |
| Group | 4 |
| Period | 5 |
| Block | d-block |
| Electron configuration | [Kr] 4d² 5s² |
| Full configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d² 5s² |
| Electrons per shell | 2, 8, 18, 10, 2 |
| Protons / electrons | 40 / 40 |
| State at 25 °C | solid |
| Melting point | 2128 K (1854.8 °C, 3370.7 °F) |
| Boiling point | 4682 K (4408.9 °C, 7967.9 °F) |
| Density | 6.506 g/cm³ |
| Electronegativity (Pauling) | 1.33 |
| First ionization energy | 6.634 eV |
| Atomic radius | 206 pm |
| Discovered | 1789 |
# Electron configuration of zirconium
The electron configuration of zirconium is [Kr] 4d² 5s², written out in full as 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d² 5s². Its 40 electrons fill 5 shells as 2, 8, 18, 10, 2, so the outermost shell holds 2 electrons.
# Related elements
YYttriumprevious elementNbNiobiumnext elementTiTitaniumgroup 4HfHafniumgroup 4RfRutherfordiumgroup 4ScScandiumtransition metalVVanadiumtransition metalCrChromiumtransition metalMnManganesetransition metalFeIrontransition metalCoCobalttransition metalNiNickeltransition metalCuCoppertransition metal
# Zirconium FAQ
What is the atomic number of zirconium?
The atomic number of zirconium is 40: every zirconium atom has 40 protons in its nucleus. Its symbol is Zr.
What is the atomic mass of zirconium?
The standard atomic mass of zirconium is 91.224 u.
What is the electron configuration of zirconium?
Zirconium's electron configuration is [Kr] 4d² 5s² (1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d² 5s²), with 2, 8, 18, 10, 2 electrons per shell.
Is zirconium a metal?
Yes. Zirconium is a transition metal, one of the metals.
What is the melting point of zirconium?
Zirconium melts at 2128 K (1854.8 °C, 3370.7 °F) and boils at 4682 K (4408.9 °C, 7967.9 °F).
What is zirconium used for / known for?
Resists corrosion and absorbs few neutrons, so it clads nuclear fuel rods; cubic zirconia is a diamond simulant.