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.
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Bohr model · educational
Bohr model of iodine
Iodine (I) has 53 electrons, spread over 5 shells. The diagram places them on circles around the nucleus, from the K shell — the closest — outward.
| Shell | Electrons |
|---|---|
| K (n = 1) | 2 |
| L (n = 2) | 8 |
| M (n = 3) | 18 |
| N (n = 4) | 18 |
| O (n = 5) | 7 |
The Bohr model is a teaching picture: electrons do not travel in circular orbits, but the number of electrons per shell is exact.
Related lesson
Chemical equilibria
Reversible reaction, reaction quotient Q, equilibrium constant K. Evolution criterion.
11 minElectron 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.
Warm-up
Iodine — do you remember?
3 questions on this page. The right answer shows every time, and nothing is asked of you to play.
No account · one minute