what is astatine black
Astatine is a semi-metallic chemical element classified among the halogens in the periodic table of elements.Periodic table of the chemical elements is a tabular display of the elements in order of atomic number, in which elements with similar properties are grouped in columns.owever, the halogens also include Astatine (At). Astatine is the rarest naturally occurring element, with less than 30 grams estimated to be contained in the entire Earthâs crust.
Astatine is a very rare radioactive chemical element with the chemical symbol At and atomic number 85. It occurs on Earth as the decay product of various heavier elements.All its isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. Elemental astatine has never been viewed because any macroscopic sample would be immediately vaporized by its radioactive heating.ighter astatine isotopes have quite high energies of alpha decay, which become lower as the nuclei become heavier. Astatine-211 has a significantly higher energy than the previous isotope, because it has a nucleus with 126 neutrons, and 126 is a magic number corresponding to a filled neutron shell.