SymbolAt
Latin nameAstatum
Atomic number85
Period6
Element categoryHalogens
Relative atomic mass209.9871
GroupVII.A
Electronegativity
2.2
Oxidation numbers
-1, 1, 3, 5, 7
Electron configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p5
State
Solid
Melting point [°C]
302
Boiling point [°C]
330
Atomic radius [pm]
127
Thermal conductivity [W m-1K-1]
1.7
Discovery
1940
1.st ionization energy [eV]
9.5
Stable isotopes
0
Unstable isotopes
21