I
Iodine Symbol (I)
Iodine is element 53 of the periodic table. Copy its symbol I and see its atomic weight, electron configuration and common compounds.
What does I mean?
I is the chemical symbol for iodine, element number 53 in the periodic table. Iodine is a halogen in group 17, period 5. It is a halogen the thyroid gland needs to make hormones, which is why table salt is often iodised.
Codes and properties
| Chemical symbol | I |
|---|---|
| Atomic number (Z) | 53 |
| Atomic weight (PubChem) | 126.9045 |
| Group / period | 17 / 5 |
| Element category | halogen |
| Electron configuration | [Kr]5s² 4d¹⁰ 5p⁵ |
| State at 20 °C | Solid |
| Oxidation states | +7, +5, +1, -1 |
| Electronegativity (Pauling) | 2.66 |
| Melting point | 386.85 K (113.70 °C) |
| Boiling point | 457.55 K (184.40 °C) |
| Density | 4.93 g/cm³ |
| Discovered | 1811 |
| Common compounds | KI, HI, I₂ |
How to type I
- Plain text: type
I— element symbols are ordinary Latin letters, with the first letter capitalised. - Subscripts in formulas: use Unicode subscript digits (₀₁₂₃₄₅₆₇₈₉) for formulas such as KI — copy them from the chemistry keyboard.
- LaTeX: write
\mathrm{I}in math mode, or use the mhchem package:\ce{I}. - HTML:
I; for subscripts use<sub>, e.g.H<sub>2</sub>O.
Frequently asked questions
What is the chemical symbol for iodine?
The chemical symbol for iodine is I.
What is the atomic number of iodine?
Iodine has atomic number 53, meaning each atom has 53 protons.
What is the electron configuration of iodine?
The ground-state electron configuration of iodine is [Kr]5s² 4d¹⁰ 5p⁵.
Related symbols
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Reference: Iodine on PubChem (NIH)