Zirconium (Zr)
Zirconium is element 40, a transition metal in period 5, group 4 of the periodic table. At room temperature it is a solid.
Electron configuration [Kr] 4d2 5s2
Electrons per shell 2, 8, 18, 10, 2
Zirconium data
| Atomic number | 40 |
|---|---|
| Symbol | Zr |
| Atomic mass | 91.224 u |
| Category | Transition metal |
| Group | 4 |
| Period | 5 |
| Block | d |
| State at 25 °C | solid |
| Melting point | 2128 K (1854.9 °C) |
| Boiling point | 4682 K (4408.9 °C) |
| Density | 6.511 g/cm³ |
| Electronegativity (Pauling) | 1.33 |
| Atomic radius | 148 pm |
| 1st ionization energy | 640 kJ/mol |
| Electron affinity | -41 kJ/mol |
| Oxidation states | +1, +2, +3, +4 |
| Common ion charge | 4+ |
| Discovered | 1789 |
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 zirconium’s configuration and its ions →
Where zirconium sits
Zirconium belongs to the transition metals. Its Pauling electronegativity of 1.33 is mid-range; see the electronegativity chart and periodic trends for context. To use its mass in a calculation, try the molar mass calculator.
Zirconium FAQ
What is the electron configuration of zirconium?
Zirconium (Z = 40) has the configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d2 5s2. In noble-gas shorthand that is [Kr] 4d2 5s2.
How many valence electrons does zirconium have?
4 (2 outer s + 2 d electrons; 2 in the outermost shell).
What is the atomic mass of zirconium?
The standard atomic weight of zirconium is 91.224 u, so one mole weighs 91.224 g.
Is zirconium a metal?
Yes. Zirconium is a transition metal.
What is the charge of a zirconium ion?
Zirconium most commonly forms Zr4+.