98
Cf
251
Californium
Actinide
Period 7
Block f
Californium is a chemical element of the periodic table with chemical symbol Cf and atomic number 98 with an atomic weight of 251 u and is classed as actinide. Californium is solid at room temperature.
Californium in the periodic table
| Symbol | Cf |
| Atomic number | 98 |
| Group | - |
| Period | 7 |
| Block | f |
| Classification | Actinide |
| Appearance | Silvery |
| Color | - |
| Number of protons | 98 p+ |
| Number of neutrons | 153 n0 |
| Number of electrons | 98 e- |
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).
Physical properties
| Phase at STP | Solid |
| Density | 15.1 g/cm3 |
| Atomic weight | 251 u |
Thermal properties
| Melting point | 1173 K 899.85 °C 1651.73 °F |
| Boiling point | 1743 K 1469.85 °C 2677.73 °F |
| Heat of vaporization | - |
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 for californium
Electron configuration Shorthand configuration | [Rn] 5f10 7s2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Full configuration | 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f10 6s2 6p6 7s2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Electron configuration chart |
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| Electrons per shell | 2, 8, 18, 32, 28, 8, 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Outer shell electrons | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Valency electrons | 2,3,4 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Bohr model | Figure: Shell diagram of Californium (Cf) atom. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Orbital Diagram
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The history of Californium
| Discovery | Lawrence Berkeley National Laboratory (1950) |
Discovery of californium Californium was first produced in February 1950 by Stanley Thompson, Kenneth Street, Albert Ghiorso and Glenn Seaborg at Berkeley by bombarding curium-242 with alpha particles. It was named after the U.S. state of California and the University of California. Californium-252 is a strong neutron emitter and is used in nuclear reactor start-ups and as a portable neutron source. | |
| Original word | California |
| Language of origin | English |
| Name source | Place |
| Meaning | “California” |
| Country | United States |
Naming The element is named after the US state of California and the University of California, where it was synthesised in 1950. | |