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Iodine (I)
Element with atomic number 53, category: Halogen, a solid at room temperature.
Element 53 of 118
Halogen
Iodine
Group 17, Period 5
Common Uses
Iodized salt, antiseptic
Electron Diagram
About Iodine
Iodine is a chemical element with the symbol I and atomic number 53, meaning every atom has 53 protons in its nucleus. It is classed as Halogen and is a solid at room temperature. Its atomic mass is about 126.904 atomic mass units (u).
On the periodic table, Iodine sits in group 17, period 5, which determines how many electron shells it has and how it tends to react with other elements.
Uses of Iodine
In daily life and industry, Iodine is used for Iodized salt, antiseptic. These uses are closely tied to the typical properties of elements in the Halogen category.
Electron Structure of Iodine
Using a simplified electron shell model (at most 2 electrons in the first shell, 8 in the second, 18 in the third, and so on), Iodine has 4 electron shells, with an approximate arrangement of 2, 8, 18, 25 electrons from the innermost shell to the outermost. This is a simplified learning model, not the full electron configuration that accounts for the s, p, d and f subshells.
Explore Other Elements
Want to see another element or try the element symbol quiz? Go back to the Interactive Periodic Table to explore all 118 chemical elements.