Outside the laboratory, francium is extremely rare, with trace amounts found in uranium ores, where the isotope francium-223 (in the family of uranium-235) continually forms and decays. It was the last element first discovered in nature, rather than by synthesis. Before its discovery, francium was referred to as eka- caesium or ekacaesium because of its conjectured existence below caesium in the periodic table. Obtaining such a sample is highly improbable since the extreme heat of decay resulting from its short half-life would immediately vaporize any viewable quantity of the element.įrancium was discovered by Marguerite Perey in France (from which the element takes its name) in 1939. Because of the general appearance of the other elements in its periodic table column, it is presumed that francium would appear as a highly reactive metal if enough could be collected together to be viewed as a bulk solid or liquid. The electronic structure of a francium atom is 7s 1 thus, the element is classed as an alkali metal.īulk francium has never been seen. Francium's isotopes decay quickly into astatine, radium, and radon. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine). It is extremely radioactive its most stable isotope, francium-223 (originally called actinium K after the natural decay chain in which it appears), has a half-life of only 22 minutes. Francium is a chemical element with the symbol Fr and atomic number 87.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |