← Periodic Table
53
p🧱
I
126.9000

Iodine

Halogen

Atomic Properties

Atomic Number
53
Atomic Mass
126.9000 u
Electron Configuration
[Kr] 4d10 5s2 5p5
Electronegativity
2.66
Block
p-block
Group
17
Period
5

🌡 Physical Properties

Phase (STP)
solid
Melting Point
386.85 K
Boiling Point
457.40 K
Density
4.9330 g/cm³

About Iodine

Essential for thyroid hormones; used as antiseptic and in photography.

🔬 Isotopes of Iodine

Iodine has 1 naturally occurring isotope.

IsotopeMass NumberAtomic Mass (u)AbundanceType
127I127126.9044719100.00%Stable

Data source: NIH PubChem (aggregated from IUPAC, NIST)