The elements with an atomic number less than their position in the periodic table are known as "transuranium elements." These elements have atomic numbers greater than 92, which is the atomic number of uranium, the last naturally occurring element. Transuranium elements are synthetic, meaning they are artificially created through nuclear reactions.
the heaviest known transuranium element is oganesson, which has an atomic number of 118. However, it's important to note that new elements may have been synthesized since then, as research in this field continues.