Discovered By: Dale R. Corson
Discovery year: 1940

The following table showing some properties of Astatine(At):

Table Example
Atomic number 85
Group 17
Period 6
Block p
Electrons 85
Protons 85
Neutrons 125
Atomic weight (210)
Oxidation states -1, +1, +3, +5, +7
Ionic charge At^-


Table Example
Electrons per shell K2 L8 M18 N32 O18 P7
Electron configuration 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^6 6s^2 4f^14 5d^10 6p^5
Atomic radius 127 pm
Covalent radius 150 pm
Melting point 302°C
Phase Solid
Fusion heat 6 kJ.mol^-1
Vaporization heat 40 kJ.mol^-1
Color Silver
Thermal conductivity 2 W.m^-1.K^-1


Table Example
Electronegativity 2.2
Valence 7
Electron affinity 270.1 kJ.mol^-1
First ionization energy 920 kJ.mol^-1
Radioactive Yes
Half life 2.9*10^4 s
Lifetime 4.2*10^4 s
Decay mode Positron emission (β+-decay)