Francium

Francium • Alkali Metal

Symbol: Fr
Date of discovery: 1939
Name origin: France
Appearance: unknown
Discoverer: Marguerite Perey
Obtained from: decay of actinium

Melting point: 300 K
Boiling point: 950 K
Density[kg/m³]: unknown
Molar volume: unknown
Protons/Electrons: 87
Neutrons: 136
Shell structure: 2,8,18,32,18,8,1
Electron configuration: [Rn]7s1
Oxidation state: 1
Crystal structure: cubic

While its existence was predicted by Mendeleev in the late nineteenth century, francium was discovered in 1939 by Marguerite Perey of the Curie Institute in Paris. She named the new element after her country, France. It is the last element to be discovered in nature and has the lowest electronegativity and electron affinity of all the elements. Francium is the second rarest element found in the earth’s crust. It is the longest-lived isotope of actinium, with a half life of about 22 minutes.