Californium (Cf) is chemical element 98, an actinide in the f-block, period 7 (PubChem).
- Atomic number: 98
- Symbol: Cf
- Group: none (f-block)
- Period: 7
- Atomic mass: 251.07959 u
- Electron configuration: [Rn]7s2 5f10
- Electronegativity (Pauling scale): 1.3
- Atomic radius (van der Waals): 245 pm
- Ionization energy: 6.30 eV
- Oxidation states: +3
- Standard state: Solid
- Melting point: 1173 K
- Chemical group: Actinide
- Year discovered: 1950