87 Fr 223

Francium

alkali metal

Properties

Atomic number
87
Atomic mass
223 u
Category
alkali metal
Group
1
Period
7
Block
s-block
State (room temp)
Solid
Outer-shell electrons
1
Electronegativity
0.79 (Pauling)
Density
1.87 g/cm³
Melting point
26.85 °C
Boiling point
676.85 °C

Electron configuration

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s¹

Noble-gas shorthand: [Rn] 7s¹

Electrons per shell: 2, 8, 18, 32, 18, 8, 1, which is 1 in the outermost shell.

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

Fr
Bohr model; outer-shell electrons in blue

About Francium

Francium is a chemical element with symbol Fr and atomic number 87. It used to be known as eka-caesium and actinium K. It is the second-least electronegative element, behind only caesium. Francium is a highly radioactive metal that decays into astatine, radium, and radon.

Francium: frequently asked questions

What is Francium?
Francium (Fr) is the chemical element with atomic number 87. It is a metal: specifically an alkali metal.
What is the atomic number of Francium?
Francium's atomic number is 87, which means every Francium atom has 87 protons in its nucleus.
What is the electron configuration of Francium?
The electron configuration of Francium is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s1 (noble-gas shorthand: [Rn] 7s1). Its electrons are arranged in shells of 2, 8, 18, 32, 18, 8, 1, with 1 in the outermost shell.
Is Francium a metal or a nonmetal?
Francium is a metal: specifically an alkali metal.
What group and period is Francium in?
Francium is in group 1 and period 7 of the periodic table.
Is Francium a solid, liquid, or gas?
At room temperature, Francium is a solid.

Position in the periodic table

Open the interactive periodic table →

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