To share this content with an AI assistant
53I126.904

Iodine

HalogensBlock pPeriod 5Group 17solid at 20 °C
Configuration :
[Kr] 4d¹⁰ 5s² 5p⁵
Atomic mass :
126.90447 u
French :
Iode
3D Bohr-model representation of the Iodine atom (symbol I, atomic number Z=53). Electron shell configuration: 2, 8, 18, 18, 7 electrons.
Scroll to activate 3D
Bohr model · educational
Related lesson

Chemical equilibria

Reversible reaction, reaction quotient Q, equilibrium constant K. Evolution criterion.

11 min
Start

Electron configuration

Full1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁵
Short[Kr] 4d¹⁰ 5s² 5p⁵
Valence electrons7
KLMNOPQ shells
K2
L8
M18
N18
O7

Electronegativity

Pauling2.66
Allen2.359
Mulliken (eV)

Atomic radii

Empirical140 pm
Calculated115 pm
Covalent139 pm
Van der Waals198 pm
Ionic radii (Shannon-Prewitt)
-1220 pm

Successive ionisation energies

I₁1008.4 kJ/mol
I₂1845.9 kJ/mol
I₃3180 kJ/mol
Electron affinity295.2 kJ/mol

Oxidation states

-1+1+3+4+5+6+7
Bold states = most common.
Period 5Block pIUPAC Group 17Family Halogens
Sources : NIST Atomic Weights & Isotopic Compositions, IUPAC Recommendations, CODATA. Methodology