Francium
Francium is the second-most electropositive element, behind only caesium. It is extremely radioactive; its most stable isotope, francium-223, has a half-life of only 22 minutes. The electronic structure of a fran calcium atom is 7s1, and so the element is classed as an alkali metal.
About Francium in brief
Francium is a chemical element with the symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223, has a half-life of only 22 minutes. Francium is the second-most electropositive element, behind only caesium, and the second rarest naturally occurring element. The electronic structure of a fran calcium atom is 7s1, and so the element is classed as an alkali metal. Outside the laboratory, trace amounts are found in uranium and thorium ores, where the isotope franium-223 continually forms and decays. As little as 20–30 g exists at any given time throughout the Earth’s crust; the other isotopes are entirely synthetic. The melting point is uncertain because of the element’s extreme rarity and radioactivity; a different extrapolation based on Dmitri Mendeleev’s method gave 20±1. 5 °C. The estimated boiling point of 620 °c is also uncertain; the estimate 598 °C, as well as the extrapolation from Mendeleeva’s method of 640 ° C, have also been suggested. The density of francia is expected to be around 2. 48 gcm3. Linus Pauling estimated the electronegativity of froncium at 0. 7 on the Pauling scale, the same as caesiam.
Fran calcium is expected to have a more lighter character than its superoxide covalent character. This is attributed to the electrons in franodium being more congeners in the fran Sodium–oxygen–gen bond. This coprecipitation method can be used to isolate small amounts offrancium, by adapting the radiocentric method of Lawrence E. Nelson and Cin Cenden M. Nelson. This method of radiocompetence can be adapted to isolate franassium, which results in small amounts of caesIUM perchlorate, which is used in caesarium salts. The largest amount produced in the laboratory was a cluster of more than 300,000 atoms. It should have a surface tension of 0. 05092 Nm at its melting point. If created, it would have a slightly higher ionization energy than caeusium, as would be expected from relativistic effects, and this would imply that caesanium is the less electr onegative of the two. The CsFr molecule is predicted to have a negative end of the dipole, unlike all known heteriatomic alkaliMetal molecules at the negative end. The element should also have a higher electron affinity than caedium and the Fr− ion− ion.
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This page is based on the article Francium published in Wikipedia (as of Dec. 03, 2020) and was automatically summarized using artificial intelligence.
