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85At210

Astatine

HalogensBlock pPeriod 6Group 17solid at 20 °C
Configuration :
[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵
Atomic mass :
210 u
French :
Astate
3D Bohr-model representation of the Astatine atom (symbol At, atomic number Z=85). Electron shell configuration: 2, 8, 18, 32, 18, 7 electrons.
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Electron configuration

Full1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁵
Short[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁵
Valence electrons7
KLMNOPQ shells
K2
L8
M18
N32
O18
P7

Electronegativity

Pauling2.2
Allen
Mulliken (eV)

Atomic radii

Empirical127 pm
Calculated
Covalent150 pm
Van der Waals202 pm

Successive ionisation energies

I₁899 kJ/mol
Electron affinity233 kJ/mol

Oxidation states

-1+1+3+5+7
Bold states = most common.
Period 6Block pIUPAC Group 17Family Halogens
Sources : NIST Atomic Weights & Isotopic Compositions, IUPAC Recommendations, CODATA. Methodology