Element 26
Iron (Fe)
Iron (Fe) is element 26 of the periodic table, a transition metal in period 4, group 8 (d-block) with an atomic mass of 55.845 and is a solid at standard conditions.
At a glance
- Atomic number
- 26
- Symbol
- Fe
- Atomic mass
- 55.845 u
- Category
- Transition metals
- Period
- 4
- Group
- 8
- Block
- d-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d6 4s2
- Shorthand configuration
- [Ar] 3d6 4s2
- Electrons per shell
- 2, 8, 14, 2
- Oxidation states
- -4, -2, -1, +1, +2, +3, +4, +5, +6, +7
Physical properties
- Melting point
- 1811 K
- Boiling point
- 3134 K
- Density
- 7.874 g/cm3
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 1.83
- Atomic radius
- 156 pm
- Covalent radius
- 132 pm
- First ionization energy
- 762 kJ/mol
- Electron affinity
- 15 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| Fe-56 | 55.93494 | 91.75% | Stable |
Common uses
- Steel production
- Construction
- Machinery
- Hemoglobin
Discovery
- Discovered by
- Known since antiquity
- Country
- Unknown