High Quality Content by WIKIPEDIA articles! In chemistry, transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92 (the atomic number of uranium). None of these elements are stable; they decay radioactively into other elements. Of the elements with atomic numbers 1 to 92, all but four (technetium, promethium, astatine, and francium) occur in easily detectable quantities on earth, having stable, or very long half-life isotopes, or are created as common products of the decay of uranium.