nuclear physics

Elements with atomic number from 1 (hydrogen) up to 92 (uranium) are naturally occuring. Elements with atomic number 93 and above (commonly callled transuranic elements) are new elements that are produced artificially.

The process of changing one element into another is called transmutation. The two main ways that a transuranic nuclei can be produced are by bombarding a nucleus with ions or neutrons. These ions or neutrons can be captured by the target nucleus and produce heavier nuclei.
Only three of the transuranic elements, those with atomic numbers 93, 94 and 95, have been produced in nuclear reactors by neutron bombardment. Transuranic elements from atomic number 96 and up are all made by accelerating a small charged nucleus (such as He, B or C) in a charged particle accelerator to collide with a heavy nucleus (often of a previously made transuranic element) target. For example, the nuclear fusion of californium-249 and carbon-12 creates the new element rutherfordium (atomic number 104, mass number 267).Therefore, fusion reaction has been used in new element production. Nuclear fission, which tends to split heavy atoms into lighter ones, is not suitable for producing transuranic elements.