26Fe55.845

Fer

Transition metalsBlock dPeriod 4Group 8solid at 20 °C
Configuration :[Ar] 3d⁶ 4s²
Atomic mass :55.845 u
English :Iron
Latin :Ferrum
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Modèle de Bohr · pédagogique

Electron configuration

Full1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ 4s²
Short[Ar] 3d⁶ 4s²
Valence electrons8
KLMNOPQ shells
K2
L8
M14
N2

Electronegativity

Pauling1.83
Allen1.8
Mulliken (eV)

Atomic radii

Empirical140 pm
Calculated156 pm
Covalent132 pm
Van der Waals
Ionic radii (Shannon-Prewitt)
+278 pm
+364.5 pm

Successive ionisation energies

I₁762.5 kJ/mol
I₂1561.9 kJ/mol
I₃2957 kJ/mol
I₄5290 kJ/mol
I₅7240 kJ/mol
Electron affinity15.7 kJ/mol

Oxidation states

-4-2-10+1+2+3+4+5+6+7
Bold states = most common.
Period 4Block dIUPAC Group 8Family Transition metals
Sources : NIST Atomic Weights & Isotopic Compositions, IUPAC Recommendations, CODATA. Methodology