98 Cf 251

Californium

actinide

Properties

Atomic number
98
Atomic mass
251 u
Category
actinide
Group
f-block
Period
7
Block
f-block
State (room temp)
Solid
Outer-shell electrons
2
Electronegativity
1.3 (Pauling)
Density
15.1 g/cm³
Melting point
899.85 °C
Boiling point
1469.85 °C

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹⁰

Noble-gas shorthand: [Rn] 5f¹⁰ 7s²

Electrons per shell: 2, 8, 18, 32, 28, 8, 2, which is 2 in the outermost shell.

Related: electron configuration, the Bohr model, valence electrons.

Cf
Bohr model; outer-shell electrons in blue

About Californium

Californium is a radioactive metallic chemical element with symbol Cf and atomic number 98. The element was first made in 1950 at the University of California Radiation Laboratory in Berkeley, by bombarding curium with alpha particles (helium-4 ions). It is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium).

Californium: frequently asked questions

What is Californium?
Californium (Cf) is the chemical element with atomic number 98. It is a metal: specifically an actinide.
What is the atomic number of Californium?
Californium's atomic number is 98, which means every Californium atom has 98 protons in its nucleus.
What is the electron configuration of Californium?
The electron configuration of Californium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f10 (noble-gas shorthand: [Rn] 5f10 7s2). Its electrons are arranged in shells of 2, 8, 18, 32, 28, 8, 2, with 2 in the outermost shell.
Is Californium a metal or a nonmetal?
Californium is a metal: specifically an actinide.
What group and period is Californium in?
Californium sits in the f-block (the actinide row) of period 7 on the periodic table.
Is Californium a solid, liquid, or gas?
At room temperature, Californium is a solid.

Position in the periodic table

Open the interactive periodic table →

Data compiled from Wikipedia, PubChem, and IUPAC. Source.