- Atomic Radius (Å)
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.
85
Atomic Number
210
Atomic Mass (u)
575.15
Melting Point (K)
610
Boiling Point (K)
6.35
Density (solid: g/cm³, gas: g/liter)
1.4
Atomic Radius (Å)
1.5
Covalent Radius (Å)
2.2
Electronegativity
9.3
First Ionization Energy (eV)
233
Electron Affinity
6
Number of Shells
7
Electron Valency
2, 8, 18, 32, 18, 7
Electron Shell Occupations