Element 53
Iodine (I)
Iodine (I) is element 53 of the periodic table, a halogen in period 5, group 17 (p-block) with an atomic mass of 126.9 and is a solid at standard conditions.
At a glance
- Atomic number
- 53
- Symbol
- I
- Atomic mass
- 126.9 u
- Category
- Halogens
- Period
- 5
- Group
- 17
- Block
- p-block
- Phase at STP
- solid
Electron structure
- Electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p5
- Shorthand configuration
- [Kr] 4d10 5s2 5p5
- Electrons per shell
- 2, 8, 18, 18, 7
- Oxidation states
- -1, +1, +3, +4, +5, +6, +7
Physical properties
- Melting point
- 386.85 K
- Boiling point
- 457.4 K
- Density
- 4.93 g/cm3
- Phase
- solid
Atomic properties
- Electronegativity (Pauling)
- 2.66
- Atomic radius
- 115 pm
- Covalent radius
- 139 pm
- Van der Waals radius
- 198 pm
- First ionization energy
- 1008 kJ/mol
- Electron affinity
- 295 kJ/mol
Notable isotopes
| Isotope | Mass | Abundance | Stability |
|---|---|---|---|
| I-127 | 126.90447 | 100% | Stable |
Common uses
- Medicine
- Photography
- Disinfectants
- Table salt
Discovery
- Year
- 1811
- Discovered by
- Bernard Courtois
- Country
- France