A

David

Darling

francium (Fr)

Francium (Fr) is a radioactive alkali metal, resembling cesium, which has been obtained only in trace quantities. Its most stable isotope, 223Fr, has a half-life of 21 minutes.

 

atomic number 87
relative atomic mass 223.02
relative density 2.5
melting point 27°C (81°F)
boiling point 677°C (1,251°F)