#85
Astatine
metalloid· Solid·210 u
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.
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Identity
- Symbol
- At
- Atomic Number
- 85
- Atomic Mass
- 210 u
- Category
- metalloid
- Block
- p-block
- Period
- 6
- Group
- 17
- Appearance
- unknown, probably metallic
- Year Discovered
- 1940 CE
- Discovered By
- Dale R. Corson
- Named By
- instability
Electrons
- Configuration
- [Xe] 4f14 5d10 6s2 6p5
- Full Configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p5
- Shells
- 2, 8, 18, 32, 18, 7
- Electronegativity
- 2.2
- Electron Affinity
- 233
- Oxidation States
- 7, 5, 3, 1, -1
- Ionization Energies
- 899.003
Physical Properties
- State at
- Solid
- Melting Point
- 575
- Boiling Point
- 610
- Density
- 6.35
- Crystal Structure
- n/a
- Magnetic Ordering
- n/a
Mechanical
- Covalent Radius
- 150 pm
- Van der Waals
- 202 pm
Thermal & Electrical
- Specific Heat
- 140 J/(kg K) J/(g·K)
- Heat of Vaporization
- 40 kJ/mol kJ/mol
- Heat of Fusion
- 6 kJ/mol kJ/mol
Abundance
- Universe
- 0
- Sun
- 0
- Meteorite
- 0
- Earth's Crust
- 3e-20 ppm
- Ocean
- 0
- Human Body
- 0