I
Iodine
HalogenAtomic Number: 53 • Atomic Mass: 126.9000 u • Period: 5 • Group: 17
Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁵
Phase: Solid
Electronegativity: 2.66
Physical & Chemical Properties
Physical Properties
- •Lustrous, purple-black solid that readily sublimes to a violet gas
- •Least reactive and most electropositive of the halogens
- •Low melting and boiling points
- •Moderately soluble in water, more soluble in organic solvents
- •Forms bluish-black crystals with metallic luster
Melting Point
386.85 K (113.70 °C, 236.66 °F)
Boiling Point
457.4 K (184.25 °C, 363.65 °F)
Density
4.93 g/cm³
Electronegativity
2.66 (Pauling scale)
Chemical Properties
- •Main oxidation states are -1, +1, +5, and +7
- •Less reactive than other halogens but still forms iodides with most elements
- •Forms triiodide ions (I₃⁻) in solution with excess iodide
- •Strong oxidizing agent
- •Forms characteristic blue complex with starch
Electron Configuration
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁵Electron configuration describes how electrons are distributed in atomic orbitals, showing how they are arranged in energy levels and subshells.