Periodic table / Astatine

Overview

Astatine is a very rare radioactive chemical element with the chemical symbol At and atomic number 85. It occurs on Earth as the decay product of various heavier elements. All its isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours.

Electron configuration

The electron configuration of Astatine is [Xe] 4f14 5d10 6s2 6p5, with electron shells of 2, 8, 18, 32, 18, 7.

Physical and chemical properties

Astatine is classified as a metalloid. It has an atomic mass of 210 and exists as a solid at standard conditions, appearing as unknown, probably metallic.

Real-world uses of Astatine

Astatine is valued for its semiconducting properties and is used in electronics, alloys, and specialty chemical applications.

Interesting facts about Astatine

• Astatine has the atomic number 85 and chemical symbol At.
• It belongs to period 6, group 17 of the periodic table.
• Astatine was discovered by Dale R. Corson.

Explore Astatine interactively

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