Fermium is an artificial radioactive element discovered in 1952 through nuclear transmutation of lighter elements. It has no stable isotopes and the longest lived isotope, fermium-257, has a half-life of around 100 days. Fermium-258 has an extremely short half-life of 0.38 milliseconds, suggesting an instability in elements around this mass number in the periodic table.

1. 100
Fm
Fermio - Fermium
Mass:257 u
[Rn] 5f12
7s2
Melting point: unknown
Boiling point: unknown
Density: unknown
discovery: discovered by artificial
nuclear transmutation of lighter
elements in 1952
Fermium is not found in nature, their discovery and production is achieved by artificial
nuclear transmutation of lighter elements. It has been discovered radioactive isotopes
with mass numbers 244-259. The total weight of fermium that has been synthesized is
much less than a millionth of gram.
Spontaneous fission i the primary mode of decay for 244-Fm, 256-Fm and 258-Fm.The
longest life isotope is 257-Fm,which has a half life of about 100 days.The fermium-258
decays by spontaneous fission and has a half life of 0.38 milliseconds.This suggests the
existence of an abnormality at this point in the periodic table.