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Iodine (I)

Iodine (I) is element 53 of the periodic table, a halogen in period 5 and group 17. Its standard atomic weight is 126.90447, so one mole of iodine atoms has a mass of 126.90447 g. At room temperature it is a solid; it melts at 113.7 °C and boils at 184.4 °C.

53 I Iodine 126.90447

Period 5, group 17 · Halogen

← Te Tellurium Xe Xenon →

Atomic number	53
Symbol	I
Standard atomic weight	126.90447
Molar mass	126.90447 g/mol
Category	Halogen
Group	17
Period	5
Block	p-block
Electron configuration	[Kr] 5s² 4d¹⁰ 5p⁵
Oxidation states	+7, +5, +1, −1
Electronegativity (Pauling)	2.66
Atomic radius (van der Waals)	198 pm
First ionisation energy	10.451 eV (1008.4 kJ/mol)
Electron affinity	3.059 eV
State at room temperature	Solid
Melting point	386.85 K (113.7 °C)
Boiling point	457.55 K (184.4 °C)
Density	4.93 g/cm³
Discovered	1811

Group 17

F · Fluorine Cl · Chlorine Br · Bromine At · Astatine Ts · Tennessine

Calculate with Iodine

Molar mass of I Balance an equation Grams, moles and particles Whole periodic table

Atomic weight: IUPAC CIAAW standard atomic weight. Other properties: PubChem (U.S. National Library of Medicine, public domain). Values such as melting point and radius depend on how they were measured; check a data book for precise work.