Fermium

  • fermium, 100fm
    fermium
    pronunciationm/ (fur-mee-əm)
    mass number[257]
    fermium in the periodic table
    hydrogen helium
    lithium beryllium boron carbon nitrogen oxygen fluorine neon
    sodium magnesium aluminium silicon phosphorus sulfur chlorine argon
    potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
    rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
    caesium barium lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury (element) thallium lead bismuth polonium astatine radon
    francium radium actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson
    er

    fm

    (upq)
    einsteiniumfermiummendelevium
    atomic number (z)100
    groupgroup n/a
    periodperiod 7
    blockf-block
    element category  actinide
    electron configuration[rn] 5f12 7s2
    electrons per shell2, 8, 18, 32, 30, 8, 2
    physical properties
    phase at stpsolid (predicted)
    melting point1800 k ​(1527 °c, ​2781 °f) (predicted)
    density (near r.t.)9.7(1) g/cm3 (predicted)[1]
    atomic properties
    oxidation states+2, +3
    electronegativitypauling scale: 1.3
    ionization energies
    • 1st: 629 kj/mol
    • [2]
    other properties
    natural occurrencesynthetic
    crystal structureface-centered cubic (fcc)
    face-centered cubic crystal structure for fermium

    (predicted)[1]
    cas number7440-72-4
    history
    namingafter enrico fermi
    discoverylawrence berkeley national laboratory (1952)
    main isotopes of fermium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    252fm syn 25.39 h sf
    α 248cf
    253fm syn 3 d ε 253es
    α 249cf
    255fm syn 20.07 h sf
    α 251cf
    257fm syn 100.5 d α 253cf
    sf
    category category: fermium
    | references

    fermium is a synthetic element with the symbol fm and atomic number 100. it is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared.[3] a total of 19 isotopes are known, with 257fm being the longest-lived with a half-life of 100.5 days.

    it was discovered in the debris of the first hydrogen bomb explosion in 1952, and named after enrico fermi, one of the pioneers of nuclear physics. its chemistry is typical for the late actinides, with a preponderance of the +3 oxidation state but also an accessible +2 oxidation state. owing to the small amounts of produced fermium and all of its isotopes having relatively short half-lives, there are currently no uses for it outside basic scientific research.

  • discovery
  • isotopes
  • production
  • synthesis in nuclear explosions
  • natural occurrence
  • chemistry
  • toxicity
  • notes and references
  • further reading
  • external links

Fermium, 100Fm
Fermium
Pronunciationm/ (FUR-mee-əm)
Mass number[257]
Fermium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Er

Fm

(Upq)
einsteiniumfermiummendelevium
Atomic number (Z)100
Groupgroup n/a
Periodperiod 7
Blockf-block
Element category  Actinide
Electron configuration[Rn] 5f12 7s2
Electrons per shell2, 8, 18, 32, 30, 8, 2
Physical properties
Phase at STPsolid (predicted)
Melting point1800 K ​(1527 °C, ​2781 °F) (predicted)
Density (near r.t.)9.7(1) g/cm3 (predicted)[1]
Atomic properties
Oxidation states+2, +3
ElectronegativityPauling scale: 1.3
Ionization energies
  • 1st: 629 kJ/mol
  • [2]
Other properties
Natural occurrencesynthetic
Crystal structureface-centered cubic (fcc)
Face-centered cubic crystal structure for fermium

(predicted)[1]
CAS Number7440-72-4
History
Namingafter Enrico Fermi
DiscoveryLawrence Berkeley National Laboratory (1952)
Main isotopes of fermium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
252Fm syn 25.39 h SF
α 248Cf
253Fm syn 3 d ε 253Es
α 249Cf
255Fm syn 20.07 h SF
α 251Cf
257Fm syn 100.5 d α 253Cf
SF
Category Category: Fermium
| references

Fermium is a synthetic element with the symbol Fm and atomic number 100. It is an actinide and the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities, although pure fermium metal has not yet been prepared.[3] A total of 19 isotopes are known, with 257Fm being the longest-lived with a half-life of 100.5 days.

It was discovered in the debris of the first hydrogen bomb explosion in 1952, and named after Enrico Fermi, one of the pioneers of nuclear physics. Its chemistry is typical for the late actinides, with a preponderance of the +3 oxidation state but also an accessible +2 oxidation state. Owing to the small amounts of produced fermium and all of its isotopes having relatively short half-lives, there are currently no uses for it outside basic scientific research.