Periodic Table
72
Hf
178.49
Hafnium
Transition MetalAlmost identical radius to Zr (lanthanoid contraction); control rods.
Electronic Configuration
[Xe] 4f¹⁴ 5d² 6s²or1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 4f¹⁴ 5d² 6s²
Electron shells
2e⁻n=1
8e⁻n=2
18e⁻n=3
32e⁻n=4
10e⁻n=5
2e⁻n=6
Properties
Atomic number
72
Atomic mass
178.49 u
Category
Transition Metal
Block / Group / Period
d · 4 · 6
Valence electrons
2
Oxidation states
+4
Electronegativity
1.3
Atomic radius
208 pm
Ionization energy
659 kJ/mol
Electron affinity
0 kJ/mol
Melting point
2506 K / 2233 °C
Boiling point
4876 K / 4603 °C
Density
13.31 g/cm³
State at 25 °C
solid
Personal Notes
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