Promethium

Promethium is a radioactive metallic element with atomic number 61. It occurs in trace amounts in uranium ores and is produced chiefly by nuclear fission.

Lanthanide: A member of the 15 metallic elements from lanthanum through lutetium, characterized by filling the 4f electron shell. Promethium is one of the lanthanides, sharing their characteristic metallic chemistry.
Nuclear fission: The splitting of a heavy atomic nucleus into lighter nuclei, usually releasing neutrons and energy. Fission of uranium and plutonium produces promethium among its radioactive products.
Henry Moseley: The English physicist who established atomic number as the basis for ordering the elements. Moseley’s measurements established that an element with atomic number 61 was missing.
Nuclear battery: A device that converts energy from radioactive decay into electrical power or light. Promethium-147 can provide the decay energy in compact, long-lived power sources.
Neodymium: A stable metallic lanthanide with atomic number 60, used chiefly in powerful permanent magnets. Neodymium lies immediately before promethium but has stable naturally occurring isotopes.
Atomic number: The number of protons in an atom’s nucleus, which defines the chemical element. Promethium’s 61 protons distinguish it from every other element.
Neutron capture: A nuclear reaction in which an atomic nucleus absorbs a neutron. Neutron capture in nuclear fuel can help generate promethium isotopes through subsequent decays.
Ida Noddack: The German chemist who proposed in 1934 that uranium could split into smaller elements. Her fission hypothesis anticipated a route by which element 61 could be produced.
Betavoltaic device: A semiconductor device that converts energy from beta particles into electrical current. Promethium-147 beta emissions can generate electricity in betavoltaic cells.
Samarium: A metallic lanthanide with atomic number 62 and several naturally occurring isotopes. Samarium follows promethium and occurs naturally in contrast to promethium’s scarcity.

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