Transuranium element

Transuranic elements are the chemical elements with atomic number greater than 92. All of them are radioactively unstable and decay into other elements. Except for neptunium and plutonium, which have been found in trace amounts in nature, none occur naturally on Earth and they are synthetic. All elements with higher atomic numbers have been first discovered in the laboratory, with neptuna and plutonium later discovered in nature. They are all radioactive, with a half-life much shorter than the age of the Earth, so any primordial atoms of these elements, have long since decayed. The naming of transuranium elements may be a source of controversy. Some heavier elements in this series, around atomic numbers 110–114, are thought to break the trend and demonstrate increased nuclear stability. As of 2008, the cost of weapons-grade plutonium was around $4,000/gram, and californium exceeded $60,000,000 /gram. Einsteinium is the heaviest element that has been produced in macroscopic quantities. The elements are difficult and expensive to produce, and their prices increase rapidly with atomic numbers.