Fermium
Also known as: Fm · element 100 · 100Fm
- 1Fermium is classified as an actinide with the atomic number 100.
- 2It is the heaviest element produced via neutron bombardment of lighter targets.
- 3The isotope 257Fm has the longest half-life at 100.5 days.
- 4A total of 20 isotopes have been identified for this element.
- 5It is the last element capable of being prepared in macroscopic quantities.
Fermium is a synthetic chemical element; it has symbol Fm and atomic number 100.
Connections11
Most stable isotope
Fermium-257 is the longest-lived isotope of the element, with a half-life of approximately 100 days.
Chemical series
Fermium is a member of the actinide series, sharing characteristic properties with other heavy radioactive elements.
Chemical classification
Fermium is a transuranium element, meaning it has an atomic number greater than 92 and is produced synthetically.
Discovery institution
The laboratory where the chemical analysis of the Ivy Mike debris was conducted to isolate and identify fermium.
Lead discoverer
Albert Ghiorso led the team at the Lawrence Berkeley National Laboratory that first identified fermium in 1952.
Site of initial discovery
Fermium was first identified in the radioactive debris collected from the Ivy Mike nuclear test in 1952.
element named in his honor
The synthetic chemical element with atomic number 100 was named after Fermi to recognize his pioneering work in nuclear physics.
Primary decay mode
Spontaneous fission is a significant decay mode for heavier isotopes of fermium, limiting the ability to produce larger quantities.
Synthesis mechanism
Fermium is produced in nuclear reactors through successive neutron capture by lighter actinides followed by beta decay.
Research context
Researchers at Los Alamos were heavily involved in the analysis of the nuclear debris from the Ivy Mike test where fermium was discovered.
Synthesis process
The production of fermium from uranium involves a series of neutron captures followed by successive beta decays to increase the atomic number.
Fermium is a synthetic chemical element identified by the symbol Fm and the atomic number 100. As a member of the actinide series, it holds the distinction of being the heaviest element that can be produced through the neutron bombardment of lighter elements. Because of this production method, it is considered the final element that can be synthesized in macroscopic quantities, although researchers have not yet successfully prepared a pure sample of fermium metal.
Reactor team from University of Chicago. Chicago Pile One scientists at the University of Chicago on December 2, 1946, the fourth anniversary of their success. Back row, from left: Norman Hilberry , Samuel Allison , Thomas Brill, Robert Nobles, Warren Nyer, and Marvin Wilkening. Middle row: Harold Agnew , William Stur...Wikimedia Commons; http://www.lanl.gov/worldview/welcome/history/08_chicago-reactor.html Source: en:Image:ChicagoPileTeam.png; Attribution; Wikimedia Commons: FermiumThe element was named after Enrico Fermi.Wikimedia Commons; Department of Energy-Office of Public Affairs, restored by Yann; This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing .; Public domain; Wikimedia Commons: Ferm...A fermium-ytterbium alloy used for measuring the enthalpy of vaporization of fermium metal. The fermium content of this fermium alloy is 4 × 10 −5 weight percent.Wikimedia Commons; Ben E. Lewis.; Oak Ridge National Laboratory; Public domain; Wikimedia Commons; Wikidata P18 (image) There are 20 known isotopes of this element, all of which are radioactive. Among these, 257Fm is recognized as the longest-lived isotope, possessing a half-life of 100.5 days. Due to its synthetic nature and short half-life, fermium does not occur naturally and must be created in specialized laboratory environments.