Periodic table / Iodine

Overview

Iodine is a chemical element with symbol I and atomic number 53. The name is from Greek ἰοειδής ioeidēs, meaning violet or purple, due to the color of iodine vapor. Iodine and its compounds are primarily used in nutrition, and industrially in the production of acetic acid and certain polymers.

Electron configuration

The electron configuration of Iodine is [Kr] 4d10 5s2 5p5, with electron shells of 2, 8, 18, 18, 7.

Physical and chemical properties

Iodine is classified as a nonmetal. It has an atomic mass of 126.904 and exists as a solid at standard conditions, appearing as lustrous metallic gray, violet as a gas.

Real-world uses of Iodine

Iodine plays an important role in chemistry and biology, and is used in industrial processes, manufacturing, or as a key component of compounds essential to life.

Interesting facts about Iodine

• Iodine has the atomic number 53 and chemical symbol I.
• It belongs to period 5, group 17 of the periodic table.
• Iodine was discovered by Bernard Courtois.

Explore Iodine interactively

Want to compare Iodine with other elements or see it highlighted on the full table? Open the interactive periodic table and click on I to explore properties, trends, and neighboring elements. You can also test your knowledge with our periodic table quiz game.