Astatine (
atomic number 85) is what happens in
nature when that
naughty radioactive misfit of the
actinide series,
uranium, decays. The least
unstable naturally occurring
isotope is 219, with a
half life of 0.9 minutes, though that of the artificially created 210 is 8.3 hours.
Shell structure is 2.8.18.32.18.7;
ground state configuration is
Xe.4f
14.5d
10.6s
2.6p
5 Fat chance any visible amount will ever be created, making astatine one of the
kung-fu space ninjas of the chemical world, leaving chemists puzzling and making half-assed guesses about its chemical properties in its non-existent wake.