Discovered | Characteristics

Francium is the heaviest element in the alkali metals, Group IA. It is in the 7th period. Other members of the group are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).

It was discovered in 1939 by Mlle. M. Perey at the Curie Institute in Paris. It results from the alpha decay of actinium.

227Ac 4He + 223Fr

223Fr is the only isotope occurring naturally, but it has a half-life of only 22 minutes. Indeed, Fr is among the most unstable of all of the elements.

At any one time is there is probably no more than an ounce of Fr in the earth's crust. No weighable quantity of Fr has been prepared or isolated, so little is known of its chemistry. Nonetheless, Fr probably resembles cesium.