85AtAstatine210[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵
metalloid
Astatine
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.
A stylized shell model. Electrons are quantum objects, not particles following these literal paths. Sizes and motion are illustrative.
Electrons by shell
Electron configuration
4f14
5d10
6s2
6p5
54 is the [Xe] core total across five shells.
At a glance
- Atomic number
- 85
- Atomic mass
- 210 u
- Phase
- Solid
- Density
- 6.35 g/cm³
- Melting point
- 575 K
- Boiling point
- 610 K
- First ionization energy
- 899.003 kJ/mol
- Electronegativity
- 2.2
- Electron affinity
- 233 kJ/mol
- Molar heat capacity
- Unavailable
- Period
- 6
- Appearance
- unknown probably metallic
Conditions and isotopes affect measured properties. Some properties of short-lived elements are predicted. Electronegativity uses the Pauling scale.
Keep exploring
Explore the stories, imagery, and reference data in more depth. Properties with no value in the reference are marked unavailable.