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Francium is a chemical element; it has 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 in which it appears), has a half-life of only 22 minutes.
Of elements whose most stable isotopes have been identified with certainty, francium is the most unstable. All elements with atomic number of 106 or greater have most-stable-known isotopes shorter than that of francium, but as those elements have only a relatively small number of isotopes discovered, the possibility remains that undiscovered ...
Francium and radium make up the s-block elements of the 7th period. Francium (Fr, atomic number 87) is a highly radioactive metal that decays into astatine, radium, or radon. It is one of the two least electronegative elements; the other is caesium. As an alkali metal, it has one valence electron.
This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
The darker more stable isotope region departs from the line of protons (Z) = neutrons (N), as the element number Z becomes larger. This is a list of chemical elements by the stability of their isotopes. Of the first 82 elements in the periodic table, 80 have isotopes considered to be stable. [1] Overall, there are 251 known stable isotopes in ...
Francium chloride is a radioactive chemical compound with the formula FrCl. It is a salt predicted to be a white solid and is soluble in water.
Astatine is an extremely radioactive element; all its isotopes have half-lives of 8.1 hours or less, decaying into other astatine isotopes, bismuth, polonium, or radon. Most of its isotopes are very unstable, with half-lives of seconds or less.
Perey named the element francium, after her home country, and it joined the other alkali metals in Group 1 of the periodic table of elements. [3] [7] Francium is the second rarest element (after astatine) — only about 550g exists in the entire Earth's crust at any given time — and it was the last element to be discovered in nature. [5] [6 ...