astatine (At) [Gk, astasis, unsteady] , a very unstable, radioactive element that occurs naturally in minute amounts. Its atomic number is 85; the atomic mass of its longest lived isotope is 210.
astatine (At) [Gk, astasis, unsteady] , a very unstable, radioactive element that occurs naturally in minute amounts. Its atomic number is 85; the atomic mass of its longest lived isotope is 210.