27Co58.933
Cobalt
Transition metal · element 27 · group 9, period 4
Quick facts
| Symbol | Co |
|---|---|
| Atomic number | 27 |
| Relative atomic mass | 58.933 |
| Category | Transition metal |
| Position | group 9, period 4 |
| State at 20 °C | Solid |
| Melting point | 1,495 °C |
| Boiling point | 2,927 °C |
| Density | 8.9 g/cm³ |
| Electronegativity | 1.88 |
| Electron configuration | [Ar] 3d7 4s2 |
About Cobalt
Cobalt has the symbol Co and atomic number 27, which means every cobalt atom has 27 protons in its nucleus and, in a neutral atom, 27 electrons. At room temperature it is a solid.
Transition metals sit in the middle block of the periodic table. They are usually hard, dense and strong, often form coloured compounds, can have more than one ion charge, and many are useful catalysts.
It melts at 1,495 °C and boils at 2,927 °C.
Explore it
See where cobalt sits, and drag the temperature slider to watch it melt and boil, on the interactive periodic table. Practise with quizzes on OmniEx.