Cf
Californium
Element 98 · Actinide
Californium (Cf)
Californium is a radioactive metal and an intense neutron source. It is one of the most expensive materials ever made.
- Actinide
- Period 7
- f-block series
- f-block
- solid at room temperature
- ☢ Radioactive
Key properties
- Atomic mass
- [251]
- u
- Electron configuration
- [Rn] 5f10 7s2
- Melting point
- 899.9 °C
- 1,173 K
- Boiling point
- 1,469.9 °C
- 1,743 K
- Density
- 15.1 g/cm³
- Electronegativity
- 1.3
- Pauling
- Atomic radius
- 245 pm
- van der Waals
- 1st ionisation energy
- 6.3 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about californium
- 01
One microgram of californium-252 gives off about 2.3 million neutrons per second.
- 02
Californium is used to start up nuclear reactors and to find gold and oil deposits.
- 03
It is the heaviest element made in amounts large enough to be used commercially.
Applications
What is californium used for?
- Neutron sources for reactor startup
- Detecting explosives and metal fatigue
- Cancer treatment research
- Oil well logging
History
Discovery & name origin
Discovered by
Stanley G. Thompson, Kenneth Street Jr., Albert Ghiorso, Glenn T. Seaborg
Year
Where
United States
Name origin
From California.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 98
- Atomic mass
- [251] u
- Group
- Actinides (3)
- Period
- 7
- Block
- f-block
- Electron configuration
- [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
- Electronegativity (Pauling)
- 1.3
- Electron affinity
- —
- Atomic radius (van der Waals)
- 245 pm
- Stable isotopes
- None — all isotopes are radioactive
Oxidation states
Highlighted: common oxidation states (+3).
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 1,173 K · 899.9 °C · 1,651.7 °F
- Boiling point
- 1,743 K · 1,469.9 °C · 2,677.7 °F
- Density
- 15.1 g/cm³
- Molar heat capacity
- —
- Appearance
- Silvery
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Californium questions
What is Cf on the periodic table?
Cf is the symbol for californium, element 98 on the periodic table. It sits in period 7, in the f-block, in the actinide category, and has an atomic mass of [251].
What is the atomic number of californium?
Californium has atomic number 98, so every californium atom has 98 protons in its nucleus. Its symbol is Cf and its atomic mass is [251].
Who discovered californium?
Californium was discovered by Stanley G. Thompson, Kenneth Street Jr., Albert Ghiorso and Glenn T. Seaborg in 1950 (United States). The name comes from from California.
What is californium used for?
Californium is used for: neutron sources for reactor startup; detecting explosives and metal fatigue; cancer treatment research; oil well logging.
Is californium a metal?
Yes. Californium is a actinide, one of the metallic elements.
What is the electron configuration of californium?
The electron configuration of californium is [Rn] 5f10 7s2. Its 98 electrons are arranged in shells as 2, 8, 18, 32, 28, 8, 2.