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Californium (Cf)

Element 98 · actinide · group 3, period 7

Californium shell diagram: 2, 8, 18, 32, 28, 8, 2 electronsCf98
Electron shells, 2 + 8 + 18 + 32 + 28 + 8 + 2. The outer shell is highlighted - it is the only one that takes part in bonding.

Californium is element 98, a actinide in group 3 and period 7. Its electron configuration is [Rn] 5f10 7s2. The shells fill 2, 8, 18, 32, 28, 8, 2. The f-block elements draw on three subshells, so a single valence count is not meaningful for them. It commonly forms ions with a charge of +3.

Properties

Atomic number98
SymbolCf
Standard atomic weight251 u
Group3
Period7
Blockf-block
Categoryactinide
Electron configuration1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f10 6s2 6p6 7s2
Noble-gas notation[Rn] 5f10 7s2
Electrons per shell2, 8, 18, 32, 28, 8, 2
Valence electrons2 or 2
Common ionic charge+3
Electronegativity (Pauling)1.3
Protons / electrons98 / 98

Electron configuration of californium

Orbitals fill from the lowest energy upward. Writing that out for californium gives 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f10 6s2 6p6 7s2, which is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f10 6s2 6p6 7s2 in plain text.

Everything up to Rn is the same as in that noble gas, so it is usually abbreviated to [Rn] 5f10 7s2. The part outside the bracket is what does the chemistry.

SubshellElectronsCapacity
1s 2 2
2s 2 2
2p 6 6
3s 2 2
3p 6 6
3d 10 10
4s 2 2
4p 6 6
4d 10 10
4f 14 14
5s 2 2
5p 6 6
5d 10 10
5f 10 14
6s 2 2
6p 6 6
7s 2 2

Californium ion charge

Californium commonly forms ions with a charge of +3.

Common questions

How many valence electrons does californium have?

There is no single agreed answer for californium. The f-block elements draw on three subshells, so a single valence count is not meaningful for them. Check which convention your course uses before answering.

What is the electron configuration of californium?

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f10 6s2 6p6 7s2, or [Rn] 5f10 7s2 written from the previous noble gas. Orbitals fill lowest energy first.

What is the charge of californium?

Californium commonly forms ions with a charge of +3. Transition metals have several accessible oxidation states, which is why more than one charge is listed.

How many protons, electrons and neutrons does californium have?

A neutral californium atom has 98 protons and 98 electrons. Its standard atomic weight is 251, so the most common isotope has about 153 neutrons.

See the ionic charge of every element →

How this page was produced. The configuration was built by filling orbitals in energy order from atomic number 98 alone, not looked up. The shell counts, the valence count and the charge all follow from it. Nothing on this page is written per element.