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Astatine (At)
Element with atomic number 85, category: Halogen, a solid at room temperature.
Element 85 of 118
Halogen
Astatine
Group 17, Period 6
Common Uses
Radioactive, very rare
Electron Diagram
About Astatine
Astatine is a chemical element with the symbol At and atomic number 85, meaning every atom has 85 protons in its nucleus. It is classed as Halogen and is a solid at room temperature. Its atomic mass is about 210 atomic mass units (u).
On the periodic table, Astatine sits in group 17, period 6, which determines how many electron shells it has and how it tends to react with other elements.
Uses of Astatine
In daily life and industry, Astatine is used for Radioactive, very rare. These uses are closely tied to the typical properties of elements in the Halogen category.
Electron Structure of Astatine
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), Astatine has 5 electron shells, with an approximate arrangement of 2, 8, 18, 32, 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.