Element 27
Cobalt (Co)
Cobalt (Co) is element 27 of the periodic table, a transition metal in period 4, group 9 (d-block) with an atomic mass of 58.933 and is a solid at standard conditions.
At a glance
- Atomic number
- 27
- Symbol
- Co
- Atomic mass
- 58.933 u
- Category
- Transition metals
- Period
- 4
- Group
- 9
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d7 4s2
- Shorthand configuration
- [Ar] 3d7 4s2
- Electrons per shell
- 2, 8, 15, 2
- Oxidation states
- -3, -1, +1, +2, +3, +4, +5
Physical properties
- Melting point
- 1768 K
- Boiling point
- 3200 K
- Density
- 8.86 g/cm3
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 1.88
- Atomic radius
- 152 pm
- Covalent radius
- 126 pm
- First ionization energy
- 760 kJ/mol
- Electron affinity
- 64 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Co-59 | 58.9332 | 100% | Stable |
Common uses
- Batteries
- Superalloys
- Blue pigments
- Magnets
Discovery
- Year
- 1735
- Discovered by
- Georg Brandt
- Country
- Sweden