Periodic Table
27
Co
58.933
Cobalt
Transition MetalCo²⁺ pink, complexes blue; vitamin B₁₂ centre; magnetic.
Electronic Configuration
[Ar] 3d⁷ 4s²or1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁷ 4s²
Electron shells
2e⁻n=1
8e⁻n=2
15e⁻n=3
2e⁻n=4
Properties
Atomic number
27
Atomic mass
58.933 u
Category
Transition Metal
Block / Group / Period
d · 9 · 4
Valence electrons
2
Oxidation states
+2, +3
Electronegativity
1.88
Atomic radius
152 pm
Ionization energy
760 kJ/mol
Electron affinity
64 kJ/mol
Melting point
1768 K / 1495 °C
Boiling point
3200 K / 2927 °C
Density
8.86 g/cm³
State at 25 °C
solid
Personal Notes
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