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Atomic symbol: Fm |
Atomic number: 100 |
Atomic weight: (257) |
Atomic volume: ? |
Density: ? |
Period Number: 7 |
Group number: none |
Group name: Rare Earth, Actinides |
Element classification: Metal |
Phase at room temperature: Solid |
Melting Point: K |
Boiling point: K |
Heat of fusion: ? |
Heat of vaporization: ? |
Ionization Energy: 6.50 eV |
1st ionization energy: 627 kJ/mole |
2nd ionization energy: kJ/mole |
3rd ionization energy: kJ/mole |
Electronegativity: 1.3 |
Electron affinity: kJ/mole |
Specific heat: ? |
Heat atomization: kJ/mole atoms |
Shells: 2,8,18,32,30,8,2 |
Electron Shell Configuration: [Rn] 5f12 7s2 |
Minimum oxidation number: 0 |
Maximum oxidation number: 3 |
Minimum common oxidation number: 0 |
Maximum common oxidation no: 3 |
Appearance & Characteristics |
Structure:: ? |
Color: ? |
Hardness: mohs |
Toxicity: ? |
Characteristics: Radioactive |
Uses: ? |
Reaction with air: ? |
Reaction with 6M HCl: ? |
Reaction with 15M HNO3: ? |
Reaction with 6M NaOH: ? |
Number of isotopes: 0 |
Oxide(s): ? |
Hydride(s): ? |
Chloride(s): ? |
Atomic Radius: pm |
Ionic radius (1- ion): pm |
Ionic radius (1+ ion): pm |
Ionic radius (2- ion): pm |
Ionic radius (2+ ion): pm |
Ionic radius (3+ ion): pm |
Thermal conductivity: J/m-sec-deg |
Electrical conductivity: 1/mohm-cm |
Polarizability: 23.8 A^3 |
Source: Synthetic |
Relative abundance solar system: log |
Abundance earth's crust: log |
Estimated crustal abundance: Not Applicable |
Estimated oceanic abundance: Not Applicable |
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(Enrico Fermi) Fermium, the eighth discovered transuranium element of the actinide series, was identified by Ghiorso and co-workers in 1952 in the debris from a thermonuclear explosion in the pacific during work involving the University of California Radiation Laboratory, Argonne National Laboratory, and Los Alamos National Laboratory.
The isotope produced was the 20-hour 255Fm. During 1953 and early 1954, while discovery of elements 99 and 100 was withheld from publication for security reasons, a group from the Nobel Institute of Physics in Stockholm bombarded 238U with 16O ions, and isolated a 30-min alpha-emitter, which they ascribed to 250Fm, without claiming discovery of the element. This isotope has since been identified positively, and the 30-min half-life confirmed.
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The chemical properties of fermium have been studied solely with tracer amounts. In normal aqueous media, only the (III) oxidation state appears to exist. |
254Fm and heavier isotopes can be produced by intense neutron irradiation of lower elements, such as plutonium, using a process of successive neutron capture interspersed with beta decays until these mass numbers and atomic numbers are reached.
Sixteen isotopes of fermium are known to exist. 257Fm, with a half-life of about 100.5 days, is the longest lived. 250Fm, with a half-life of 30 minutes, has been shown to be a decay product of element 254No. Chemical identification of 250Fm confirmed the production of element 102 (nobelium).
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