Atoms of astatine (or astatine) are unstable and usually decay after a few hours into other atoms of lighter elements, such as bismuth. This radioactive element itself forms in a similar way when atoms of a heavier element called francium separate. Small amounts of this rare element are found in uranium ores, such as uraninite. Physicist Emilio Segrè was one of the first scientists to isolate a pure atom sample. He was able to do so using a particle accelerator.
Summary of properties (At)
| Atomic weight | [210] |
| Discoverer (year) | Corson, Dale R. & Mackenzie, K. R. (1940) |
| Natural form | non-metal solid (-) |
| Electron configuration | [Xe] 4f 14 5d10 6s2 6p5 |
| Melting point (ºC) | 302 |
| Boiling point (ºC) | 337 |
| Abundance in earth's crust (ppm) | <0.001 |
| Isotope (abundance) | |
| Density g/cm3 | |
| Van der Waals radius (pm) | 202 |
| Covalent radius (pm) | 148 |
| Electronegativity (Pauling) | 2.2 |
| Vaporization enthalpy (kJ/mol) | - |
| Enthalpy of fusion (kJ/mol) | - |
| Specific heat capacity (J/g·K) at 25ºC and 1 atm | - |
| Thermal conductivity (W/cm·K) at 25ºC and 1 atm | 0.020 |
| Oxidation state | |
| Electron affinity (eV) | 2.80 |
| 1st Ionization potential (eV) |
