Californium (Cf)
One microgram of californium-252 gives off about 2.3 million neutrons every second.
Californium properties
- Atomic mass
- 251 u
- Category
- Actinide
- Group
- —
- Period
- 7
- Block
- f-block
- State at room temp.
- Solid
- Melting point
- 1,173 K (899.8 °C)
- Boiling point
- 1,743 K (1,469.8 °C)
- Density
- 15.1 g/cm³
- Atomic radius
- 245 pm
- Ionization energy
- 6.3 eV
- Electron affinity
- —
- Radioactive
- Yes, no stable isotopes
- Discovered
- 1950
Californium electron configuration
- Electron configuration
- [Rn] 5f10 7s2
- Full electron configuration
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f10 6s2 6p6 7s2
- Electron shells
- 2 · 8 · 18 · 32 · 28 · 8 · 2
The electron configuration of Californium (Cf) is [Rn] 5f10 7s2. Its 98 electrons are arranged in shells as 2, 8, 18, 32, 28, 8, 2.
Protons, neutrons and electrons in Californium
A neutral Californium atom has 98 protons and 98 electrons. Most Californium atoms have about 153 neutrons: the atomic mass rounded to 251, minus the atomic number 98.
Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass
How many valence electrons does Californium have?
2
Californium has 2 valence electrons in its outermost shell. As an f-block element, its 4f or 5f electrons can also take part in bonding.
Californium orbital diagram
Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations
Molar mass of Californium
251 g/mol
One mole of Californium atoms (6.022 × 10²³ atoms) has a mass of 251 grams. Use this value to convert between grams and moles.
Californium facts
- One microgram of californium-252 gives off about 2.3 million neutrons every second.
- Californium-252 has a half-life of about 2.6 years, so sources must be replaced regularly.
- Californium (Cf) has atomic number 98 and is a solid at room temperature. It was discovered in 1950.
Position in the periodic table
Californium is element 98, in period 7 of the periodic table. It is one of the Actinides in the f-block, shown in the rows below the main table.
Uses of Californium
Californium-252 is a powerful neutron emitter, so small sources are used to start up nuclear reactors, to find water and oil layers when logging wells, and to scan luggage and cargo for explosives. It is also used in some cancer treatments and in analyzers that check the composition of coal and cement in factories.
Who discovered Californium?
Stanley Thompson, Kenneth Street Jr., Albert Ghiorso and Glenn Seaborg first made californium in 1950 at the University of California, Berkeley, by bombarding curium with alpha particles. It is named after the state of California and its university.
Where does the name come from?
Californium is named after the state of California and the University of California, where scientists working at Berkeley first produced the element in 1950 by bombarding curium with helium nuclei.
Actinide
Compare Californium
FAQ
What is the electron configuration of Californium?
The electron configuration of Californium (Cf) is [Rn] 5f10 7s2. Its 98 electrons are arranged in shells as 2, 8, 18, 32, 28, 8, 2.
How many protons, neutrons and electrons does Californium have?
A neutral Californium atom has 98 protons and 98 electrons. Most Californium atoms have about 153 neutrons: the atomic mass rounded to 251, minus the atomic number 98.
How many valence electrons does Californium have?
Californium has 2 valence electrons in its outermost shell. As an f-block element, its 4f or 5f electrons can also take part in bonding.
What is the molar mass of Californium?
The molar mass of Californium is 251 g/mol. This is the same number as its atomic mass, 251 u.
Is Californium a metal?
Yes. Californium is an actinide, so it is a metal.
Is Californium radioactive?
Yes. Californium has no stable isotopes, so all of its atoms are radioactive and eventually decay into other elements.
Where is Californium on the periodic table?
Californium is element 98, in period 7 of the periodic table. It is one of the Actinides in the f-block, shown in the rows below the main table.