Astatine - Wikipedia
网页Astatine is a chemical element; it has symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only as the decay product of various heavier elements. All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours.
Astatine | Radioactive Halogen, Uses in Medicine & Research
网页Astatine (At), radioactive chemical element and the heaviest member of the halogen elements, or Group 17 (VIIa) of the periodic table. Astatine, which has no stable isotopes, was first synthetically produced (1940) at the University of California by American physicists Dale R. Corson, Kenneth R.
Astatine - Element information, properties and uses | Periodic Table
网页Element Astatine (At), Group 17, Atomic Number 85, p-block, Mass [210]. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images.
Facts About Astatine - Live Science
网页2017年5月24日 · Astatine is the rarest element on Earth; only approximately 25 grams occur naturally on the planet at any given time. Its existence was predicted in the 1800s, but was finally discovered about 70...
Astatine Facts (Element 85 or At) - ThoughtCo
网页2020年1月2日 · Astatine is a radioactive element with symbol At and atomic number 85. It has the distinction of being the rarest natural element found in the Earth's crust, as it is only produced from radioactive decay of even heavier elements. The element is similar to its lighter congener, iodine.
Astatine Element | Uses, Facts, Physical & Chemical Characteristics
网页Astatine is the least reactive element among its group, halogens. Chemically, astatine shows metallic properties and forms stable monatomic cations in the presence of water. various compounds of astatine are like compounds of iodine. There are only few compounds of astatine.
Astatine Element - Properties, Health Effects & Uses Astatine
网页What is Astatine? Astatine is the 85th element of the periodic table with a symbol ‘At’. It is a radioactive element and is said to be the most heavier among the halogens. This element exhibits similar chemical properties that of the element iodine.
Properties of astatine | Britannica
网页astatine, Radioactive chemical element and the heaviest halogen element, chemical symbol At, atomic number 85. It was first synthetically produced in 1940 from the bombardment of bismuth by alpha particles and neutrons.
Astatine | Encyclopedia.com
网页2018年5月14日 · Astatine is a member of the halogen family, elements in Group 17 (VIIA) of the periodic table. It is one of the rarest elements in the universe. Scientists believe that no more than 25 grams exist on the Earth 's surface. All isotopes of astatine are radioactive and decay into other elements.
Astatine (At) - Periodic Table
网页Astatine is the 85th element in the periodic table and has a symbol of At and atomic number of 85. It has an atomic weight of (210) and a mass number of 191. Astatine has eighty-five protons and one hundred six neutrons in its nucleus, and eighty-five electrons in six shells.