

| Californium | Symbol | Cf radioactive rare earth metal | | Atomic Number | 98 | Relative Atomic Mass 12C = 12.0000 | [ 251 ] 251.0796 898 year / 9.0x102 year | | Significant Atomic Mass | 251 Neutrons 153 | | Atomic Radius pm | 169 | First Ionisation Energy kJ mol -1 | 608 | | Electronegativity | 1.3 | | Density kg m -3 | n/a | | Molar Volume cm 3 | n/a | Thermal Conductivity W m -1 K -1 | 10 [300 K] (est.) | | Melting Point K | 1170K = 900°C | | Boiling Point K | n/a | | Number of Isotopes | 18 |  | 249 Cf 351 year 250 Cf 13.1 year 251 Cf 898 year 252 Cf 2.65 year 253 Cf 17.8 day 254 Cf 60.5 day 255 Cf 1.4 h 256 Cf 12.3 min | | Inner + outer Shells | | | Inner + outer Orbitals | | | Filling Orbital | | | Ground State Electron Configuration | | | | Ground State Electron Configuration with free Orbitals (n= 20 ) |  | | | Ground State Electron Configuration with compressed Orbitals (n= 162 ) |  | | | | Singularity | | | | | | s | p | d | f | g | h | i | j | 1 | 2 | | | | | | | | 2 | 2 | 6 | | | | | | | 3 | 2 | 6 | 10 | | | | | | 4 | 2 | 6 | 10 | 14 | | | | | 5 | 2 | 6 | 10 | 10 | 4 | 18 | | | | 6 | 2 | 6 | 10 | 14 | 18 | 22 | | | 7 | 2 | 6 | 10 | 14 | 18 | 22 | 26 | | 8 | | | | | | | | |
| | | | Term Symbol | 5I 8 | | CAS Reg-ID: | 7440-71-3 | | Discovery | Produced by S.G. Thompson, K. Street Jr., A. Ghiorso and G.T. Seaborg (Berkeley, USA) in 1950 | | Name derived from | Named after the state of California and the University of California (USA). | | Description | Californium-252 is a strong neutron emitter and one microgram emits 170 million neutrons per minute, making it a biological hazard. Proper safeguards should be used in handling californium. |
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