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Periodic table / Transition metals

26Iron

Iron is a transition metal in group 8, period 4. At 25 °C it is a solid.

Fe
Shells: 2, 8, 14, 2. A simple picture: electrons do not move in circles.
Symbol
Fe
Atomic number
26 protons in the nucleus
Standard atomic weight
55.845 ± 0.002
Electron configuration
[Ar] 3d6 4s2
Electrons in each shell
2, 8, 14, 2
Group, period, block
8, 4, d
Family
Transition metals
State at 25 °C
solid
Electronegativity
1.83 (Pauling scale)
First ionisation energy
762.5 kJ/mol (7.9024681 eV)
Where these numbers come from

Atomic weight: IUPAC CIAAW, abridged standard atomic weights 2024. Electron configuration and ionisation energy: NIST Atomic Spectra Database. Family, state and electronegativity: PubChem. See Sources. Melting points, boiling points and densities are left out for now: published values differ between sources, and we will add them once each has been checked.