27
Co
58.933
Cobalt (Co)
Element 27 · Period 4 · Group 9
transition-metal
solid at room temp
d-block
About Cobalt
Used in high-temperature alloys, magnets, and lithium-ion batteries. Vitamin B12 contains cobalt.
Physical Properties
Atomic Mass
58.933 u
State at 25°C
Solid
Melting Point
1495 °C
Boiling Point
2927 °C
Density
8.9 g/cm³
Magnetism
Ferromagnetic
Atomic Properties
Electron Configuration
[Ar] 3d⁷ 4s²
Electron Shells
2, 8, 15, 2
Electronegativity
1.88
Atomic Radius
152 pm
Ionization Energy
760 kJ/mol
Oxidation States
+2, +3
Discovery & History
Discovered By
Georg Brandt
Discovery Year
1735
Named By
Georg Brandt
Name origin: German: Kobold (goblin)
Frequently Asked Questions
- Is Cobalt a metal, nonmetal, or metalloid?
- Cobalt is classified as a transition-metal.
- What state is Cobalt in at room temperature?
- Cobalt is a solid at standard room temperature (25°C).
- What is the atomic mass of Cobalt?
- Cobalt has an atomic mass of 58.933 atomic mass units (u).
- Who discovered Cobalt?
- Cobalt was discovered by Georg Brandt in 1735.
- Where is Cobalt on the periodic table?
- Cobalt is element number 27, located in period 4 and group 9.