Atomic Element Z = 27 • Transition Metal
Cobalt (Co) — Atomic Data, Electron Shells & Reactions
Cobalt (symbol Co, atomic number 27) has a standard atomic weight of 58.933 u and ground-state configuration [Ar] 3d7 4s2.
Atomic Number (Z)
27
IUPAC Symbol
Co
Standard Atomic Weight
58.933 g/mol
Period / Group / Block
4 / 9 / d-block
Condensed Electron Config
[Ar] 3d7 4s2
Full Subshell Config
1s2 2s2 2p6 3s2 3p6 3d7 4s2
Principal Shell Occupancy
[2, 8, 15, 2]
Pauling Electronegativity
1.88
First Ionization Energy
760 kJ/mol
Covalent Radius
126 pm
Melting Point
1768 K (1494.85 °C)
Boiling Point
3200 K (2926.85 °C)
Density
8.86 g/cm³
Oxidation States
+3, +2
Co (Z=27) — Valence shell highlighted in vermilion