098Actinide · Group 3 · Period 7
Californium
Californium (Cf) is element 98, a actinide in the f-block — group 3, period 7. It is a solid at room temperature with 7 electron shells (2, 8, 18, 32, 28, 8, 2) and an atomic mass of 251 u.
- Atomic mass
- 251.0 u
- Phase · STP
- solid
- Melting
- 1173 K · 900 °C
- Boiling
- 1743 K · 1470 °C
- Electronegativity
- 1.3
- Density
- 15.1 g/cm³
Photograph — United States Department of Energy (see File:Einsteinium.jpg), Public domain, via Wikimedia Commons
Identity
- Atomic number
- 98
- Standard atomic weight
- 251.0 u
- Category
- Actinide
- Group
- 3
- Period
- 7
- Block
- f-block
- Oxidation states
- +3
Physical properties
- Melting point
- 1173 K · 900 °C
- Boiling point
- 1743 K · 1470 °C
- Density
- 15.1 g/cm³
- Molar heat capacity
- —
- Atomic radius
- 245 pm
- Electron affinity
- -97.31 kJ/mol
Atomic structure
98protons
153neutrons
98electrons
2valence e⁻
- Noble-gas notation
- [Rn] 5f10 7s2
- Full configuration
- 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f10
- Electrons per shell
- 2, 8, 18, 32, 28, 8, 2
Periodic trends
Where Californium ranks across all 118 elements.
Discovery
- Discovered
- 1950
- Discovered by
- Lawrence Berkeley National Laboratory
- Named by
- —
- Appearance
- silvery