#fermium
As the heaviest element that can be produced in macroscopic quantities, fermium is the last element capable of being produced in nuclear reactors, rather than the accelerators that heavier elements are made in.
Nevertheless, fermium is more often produced in accelerators because fermium-257, the isotope produced in reactors, easily absorbs the stray neutrons floating about and quickly becomes fermium-258, which has a very short half life.
Periodic Videos on YouTube discusses the element fermium, a synthetic element with no applications.
