85
At
210
Astatine (At)
Element 85 · Period 6 · Group 17
halogen
solid at room temp
p-block
radioactive
About Astatine
Rarest naturally occurring element. Radioactive halogen studied for cancer treatment.
Physical Properties
Atomic Mass
210 u
State at 25°C
Solid
Melting Point
302 °C
Boiling Point
337 °C
Magnetism
Paramagnetic
Atomic Properties
Electron Configuration
[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵
Electron Shells
2, 8, 18, 32, 18, 7
Electronegativity
2.2
Atomic Radius
127 pm
Ionization Energy
916 kJ/mol
Oxidation States
-1, +1, +3, +5
Discovery & History
Discovered By
Dale R. Corson
Discovery Year
1940
Named By
Dale R. Corson
Name origin: Greek: astatos (unstable)
Frequently Asked Questions
- Is Astatine a metal, nonmetal, or metalloid?
- Astatine is classified as a halogen.
- What state is Astatine in at room temperature?
- Astatine is a solid at standard room temperature (25°C).
- What is the atomic mass of Astatine?
- Astatine has an atomic mass of 210 atomic mass units (u).
- Who discovered Astatine?
- Astatine was discovered by Dale R. Corson in 1940.
- Where is Astatine on the periodic table?
- Astatine is element number 85, located in period 6 and group 17.