| From Wikipedia, the free encyclopediaCalifornium is a radioactive metallic chemical element with symbol Cf and atomic number 98. The element was first made in 1950 at the University of California Radiation Laboratory in Berkeley, by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium). | |||||||||
Californium in the periodic table | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | Cf | ||||||||
| Atomic number | 98 | ||||||||
| Group | 0 | ||||||||
| Period | 7 | ||||||||
| Block | f | ||||||||
| Element category | Actinide | ||||||||
Physical properties | |||||||||
| Phase at STP | Solid | ||||||||
| Density | 15.1 g/cm3 | ||||||||
| Atomic weight | 251 u | ||||||||
| Melting point | 1173 K 899.85 °C 1651.73 °F | ||||||||
| Boiling point | 1743 K 1469.85 °C 2677.73 °F | ||||||||
Atomic properties | |||||||||
| Electronegativity (Pauling Scale) | 1.3 | ||||||||
| Electron affinity | -97.31 kJ/mol | ||||||||
| Oxidation states | +2, +3, +4, +5 () | ||||||||
| Ionization energies |
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Electron configuration | |||||||||
| Elektronkonfiguration (shorthand) | [Rn] 5f10 7s2 | ||||||||
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f10 6s2 6p6 7s2 | ||||||||
| Electrons per shell | 2, 8, 18, 32, 28, 8, 2 | ||||||||
History | |||||||||
| Discovered | 1950 | ||||||||
| Discovered by | Lawrence Berkeley National Laboratory | ||||||||