53 I
Halogen
Iodine
Essential for thyroid function.
Properties of Iodine
- Atomic number (Z)
- 53
- Symbol
- I
- Atomic mass
- 126.9 g/mol
- Category
- Halogen
- Group
- 17
- Period
- 5
- Electron configuration
- [Kr] 4d¹⁰ 5s² 5p⁵
- Electronegativity (Pauling)
- 2.66
- Atomic radius
- 115 pm
- First ionization energy
- 1008 kJ/mol
- Melting point
- 386.85 K (113.7 °C)
- Boiling point
- 457.4 K (184.3 °C)
- Density
- 4.93 g/cm³
- Phase at 25 °C
- Solid
- Discovered
- Discovered in 1811