040Transition metal · Group 4 · Period 5
Zirconium
Zirconium (Zr) is element 40, a transition metal in the d-block — group 4, period 5. It is a solid at room temperature with 5 electron shells (2, 8, 18, 10, 2) and an atomic mass of 91.2242 u.
- Atomic mass
- 91.22 u
- Phase · STP
- solid
- Melting
- 2128 K · 1855 °C
- Boiling
- 4650 K · 4377 °C
- Electronegativity
- 1.33
- Density
- 6.52 g/cm³
Photograph — Jurii, CC BY 3.0 <https://creativecommons.org/licenses/by/3.0>, via Wikimedia Commons, source: https://images-of-elements.com/zirconium.php
Identity
- Atomic number
- 40
- Standard atomic weight
- 91.22 u
- Category
- Transition metal
- Group
- 4
- Period
- 5
- Block
- d-block
- Oxidation states
- +4
Physical properties
- Melting point
- 2128 K · 1855 °C
- Boiling point
- 4650 K · 4377 °C
- Density
- 6.52 g/cm³
- Molar heat capacity
- 25.36 J/(mol·K)
- Atomic radius
- 186 pm
- Electron affinity
- 41.806 kJ/mol
Atomic structure
40protons
51neutrons
40electrons
2valence e⁻
- Noble-gas notation
- [Kr] 4d2 5s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d2
- Electrons per shell
- 2, 8, 18, 10, 2
Periodic trends
Where Zirconium ranks across all 118 elements.
Ionization energies
Energy to remove each successive electron (kJ/mol).
640.11
1.3k2
2.2k3
3.3k4
7.8k5
9.5k6
Successive ionization energies (kJ/mol, log scale).
Discovery
- Discovered
- 1789
- Discovered by
- Martin Heinrich Klaproth
- Named by
- —
- Appearance
- silvery white