Atomic Element Z = 85 • Halogen
Astatine (At) — Atomic Data, Electron Shells & Reactions
Astatine (symbol At, atomic number 85) has a standard atomic weight of 210 u and ground-state configuration [Xe] 4f14 5d10 6s2 6p5.
Atomic Number (Z)
85
IUPAC Symbol
At
Standard Atomic Weight
210 g/mol
Period / Group / Block
6 / 17 / p-block
Condensed Electron Config
[Xe] 4f14 5d10 6s2 6p5
Full Subshell Config
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p5
Principal Shell Occupancy
[2, 8, 18, 32, 18, 7]
Pauling Electronegativity
2.2
First Ionization Energy
920 kJ/mol
Covalent Radius
150 pm
Melting Point
575 K (301.85 °C)
Boiling Point
610 K (336.85 °C)
Density
7 g/cm³
Oxidation States
-1, +1
At (Z=85) — Valence shell highlighted in vermilion