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Author: langbot
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English[en]
Francium is a chemical element with the symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223 (originally called actinium K after the natural decay chain it appears in), has a half-life of only 22 minutes. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine). The isotopes of francium 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 francium has never been seen. 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. 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.
Cornish[kw]
Elven gymyk yw frankiom, niver 87 y'n Vosen Beriodek. Y furvell yw Fr. An hanow a dheu dhyworth Pow Frynk. Hemm yw an eyl elven henwys dhyworth an wlas keffrys ha galliom. Ny gyllir kavos yw franciom y'n kerghynnedh dhe ves a arbrovjiow hwithrans marnas dognow byghan yn monow uraniom kepar ha pitchblende. Diskudhys veu yn 1939 gans Marguerite Perey y'n Fondyans Curie yn Paris. Peryllus yw awos y radyoweythresans glew. Kales yw dhe hwithra awos y hanter bewnans berr (22 mynysen).