Symbol
At
Atomic Number
85
Atomic Mass
210
Protons
85
Neutrons
125
Electrons
85
Type
Halogen
Isotopes
Astatine-210
Discovery Year
1940
Discovered By
Dale R. Corson, Emilio Segrè, and Glen T. Seaborg
Group
17
Period
6
Boiling Point
337°C
Melting Point
302°C
Electron Configuration
[Xe] 6s² 4f¹⁴ 5d¹⁰ 6p⁵
Density (g/cm³)
7
Crystal Structure
Cubic
Magnetism
Diamagnetic
Abundance in Earth's Crust
Trace
Phase at Room Temperature
Solid