Periodic table / Transition metals
72Hafnium
Hafnium is a transition metal in group 4, period 6. At 25 °C it is a solid.
- Symbol
- Hf
- Atomic number
- 72 protons in the nucleus
- Standard atomic weight
- 178.49 ± 0.01
- Electron configuration
- [Xe] 4f14 5d2 6s2
- Electrons in each shell
- 2, 8, 18, 32, 10, 2
- Group, period, block
- 4, 6, d
- Family
- Transition metals
- State at 25 °C
- solid
- Electronegativity
- 1.3 (Pauling scale)
- First ionisation energy
- 658.5 kJ/mol (6.82507 eV)
Where these numbers come from
Atomic weight: IUPAC CIAAW, abridged standard atomic weights 2024. Electron configuration and ionisation energy: NIST Atomic Spectra Database. Family, state and electronegativity: PubChem. See Sources. Melting points, boiling points and densities are left out for now: published values differ between sources, and we will add them once each has been checked.