Francium

by Emily Owen

Francium was discovered in 1939 by French scientist Margureite Perey. It was named after the nation it was discovered in, France. Francium is a radioactive element that is produced in certain nuclear reactions. It is the heaviest member in the group alkali metals. It is the most scarce of the alkali metals. There is only one ounce of natural francium in the soil and rock of the earth. It is a naturally occurring element, and because it is so scarce, all of its isotopes are radioactive and the longest half-life is less than 30 minutes. It was discovered as a product of the radioactive decay of actinium.

During the 1870’s, Dimitri Mendeleyev, predicted the exisitance of element 87. He thought its properties would be similar to those of celsium, so he named it eka-cesium. Marguerite Catherine Perey was and assistant to Marie Currie, who was a successful and respected female scientist. After Currie’s death, Perey continued her work, trying to unravel the sequence of events we now know as the actinium radioactive decay series. She knew about actinouranium, actinium-B, actinium-C, and actinium-D. When she tried to confirm her results with a more precise analyses, other elements began appearing. One of them was Francium-223. There was enough of the sample to confirm her discovery.

All elements for studying today are made artificially. There are two ways of making small quantities of Francium. The first is to bombard thorium with protons. This is the more direct approach. The more practical approach is to have it subjected to heavy neutron bombardment. Once this has happened, it is converted into a type of actinium that breaks down naturally and quickly to thorium. Next the thorium decays to francium. Francium has isotopes with atomic weights between 201 and 229.

Facts about Francium

Name Francium

Symbol Fr

Atomic number 87

Atomic weight 223(Note 1)

Melting point 27 C (Note 2)

Boiling point 677 C (Note 2)

Specific gravity ?

Oxidation number +1

Electron Configuration (Rn) 7s

* Note 1- Most stable isotope

* Note 2- Calculated value