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 …

2024年10月16日 · Astatine (At) is a rare and highly radioactive element with atomic number 85. It is part of the halogen group (Group 17) in the periodic table, which also includes fluorine, chlorine, bromine, and iodine. Unlike the other halogens, astatine has no stable isotopes.

2025年2月19日 · 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.

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 is a shiny dark colored element. Astatine is a radioactive element. It is a semiconductor and can have metallic properties. Astatine undergoes sublimation but less readily than iodine and have a low vapor pressure.

Element Astatine (At), Group 17, Atomic Number 85, p-block, Mass [210]. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images.

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 …

Astatine is a radioactive, chemical element. Its atomic number is 85, and its atomic weight is 210. It is part of the Group 17 on the periodic table of elements. All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.3 hours.

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.

2021年8月13日 · Astatine. A radioactive halogen with the atomic symbol At, and atomic number 85. Its isotopes range in mass number from 200 to 219 and all have an extremely short half-life. Astatine may be of use in the treatment of hyperthyroidism because it emits ALPHA PARTICLES.