Use
Chemists of the early twentieth century tried to find the existence of element 85, whichwas given the name “eka-iodine” by Mendeleev in order to fill the space for the missing elementin the periodic table. Astatine is the rarest of all elements on Earth and is found in onlytrace amounts. Less than one ounce of natural astatine exists on the Earth at any one time.There would be no astatine on Earth if it were not for the small amounts that are replenishedby the radioactive decay process of uranium ore. Astatine produced by this uranium radioactivedecay process soon decays, so there is no long-term build up of astatine on Earth. Theisotopes of astatine have very short half-lives, and less than a gram has ever been produced forlaboratory study.