72 - Hafnium transition metal
Discovered by Dirk Coster in 1923
- Atomic Radius (Å)
Hafnium is a chemical element with symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869, though it was not identified until 1923, making it the penultimate stable element to be discovered (rhenium was identified two years later).
Shell | Electrons | Orbitals |
---|---|---|
1 | 2 | 2 in 1s |
2 | 8 | 2 in 2s + 6 in 2p |
3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
4 | 32 | 2 in 4s + 6 in 4p + 10 in 4d + 14 in 4f |
5 | 10 | 2 in 5s + 6 in 5p + 2 in 5d |
6 | 2 | 2 in 6s |
178.49 u
Atomic Mass
2.2 Å
Atomic Radius
4876 K
Boiling Point
1.75 Å
Covalent Radius
13.31 g/cm³
Density
17.18
Electron Affinity
1.3
Electronegativity
6.83 eV
First Ionization Energy
2500.15 K
Melting Point
6
Number of Shells
72
Atomic Number
2, 8, 18, 32, 10, 2
Electron Shell Occupations