Francium is a chemical element with the symbol Fr and atomic number 87. It is the second most electropositive element, behind only caesium, and is the second rarest naturally occurring element after astatine. The isotopes of Fr decay quickly into astatine, radium, and radon. The electronic structure of a francium atom is [Rn] 7s1, and so the element is classed as an alkali metal.
Bulk Fr has never been viewed. Because of the general appearance of the other elements in its periodic table column, it is assumed that Fr would appear as a highly reactive metal, if enough could be collected together to be viewed as a bulk solid or liquid.
It was discovered by Marguerite Perey in France in 1939. It was the last element first discovered in nature, rather than by synthesis. Outside the laboratory, Francium is extremely rare, with trace amounts found in uranium and thorium ores, where the isotope francium-223 continually forms and decays. As little as 20–30 g (one ounce) exists at any given time throughout the Earth’s crust; the other isotopes (except for francium-221) are entirely synthetic. The largest amount produced in the laboratory was a cluster of more than 300,000 atoms.
Properties of Francium
- It is a least founded metal on the planet earth and rarely found in nature. It is considered to be the second rarest metal discovered on the earth’s crust next to the Astatine.
- It is produced both by naturally as well as by artificial methods. Most probably, it is assumed that about 340-550 gm of this metal francium are found in the earth’s crust.
- It occurs on the decay of the alpha particles, which are found in the minerals of uranium.
- It has about 34 isotopes that are said to be occurring in nature. Fr has the only 1-valence electron.
Uses of Fr
- It has been used in the field of research, chemistry and also in the atomic structure.
- It is used for diagnostics for curing cancers.
- It is also used in many spectroscopic experiments.
- Fr is a highly radioactive metal, and since it exhibits a short half-life, it does not have more impact on the environment.