rhónium
Rhónium is a hypothetical chemical element with the symbol Rhn and atomic number 121. As element 121, it would be the first element in the g-block of the periodic table, which is currently a theoretical concept. Its predicted electronic configuration places it as a superactinide. Due to its position, rhónium is expected to be a highly unstable transuranic element, with extremely short half-lives and no naturally occurring isotopes. Theoretical calculations suggest that its nucleus would be extremely heavy, making it prone to rapid radioactive decay, likely through alpha decay or spontaneous fission. The synthesis and detection of rhónium would require advanced particle accelerators and sophisticated detection methods, similar to those used for other superheavy elements. Its chemical properties are largely unknown and are subject to theoretical prediction. It is anticipated that its chemistry would be influenced by relativistic effects, which become increasingly significant for heavier elements, potentially leading to deviations from trends observed in lighter elements. Further research into the island of stability might provide insights into the potential for more stable isotopes of rhónium or neighboring elements, though this remains speculative.