Promethium is a rare, radioactive element with the chemical symbol Pm and atomic number 61. It belongs to the lanthanide series of the periodic table and is known for its silvery-white appearance. Promethium is not found in nature in significant amounts but can be produced synthetically in nuclear reactors. This element has applications in various fields, including nuclear batteries and luminous paint. Due to its radioactivity, promethium emits beta particles, which can be harnessed for energy. However, its use is limited due to safety concerns and the challenges associated with handling radioactive materials.