Americium

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Americium is a synthetic chemical element with the symbol Am and atomic number 95. It is a radioactive element that is part of the actinide series, which is located in the f-block of the periodic table. Americium was first produced in 1944 by a group of scientists led by Glenn T. Seaborg at the University of Chicago, making it the fourth synthetic element to be discovered. The element was named after the Americas, by analogy with europium, to emphasize the elements' discovery in a continent of the Western Hemisphere.

Properties

Americium is a silvery-white metal that has more than one allotrope. It is radioactive and primarily emits alpha particles. It has several isotopes, with americium-241 (Am-241) and americium-243 (Am-243) being the most common and stable. Am-241 has a half-life of 432.2 years, making it useful in commercial smoke detectors, as well as in nuclear batteries and neutron sources.

Production

Americium is not found naturally and is produced by bombarding plutonium with neutrons in nuclear reactors. The most common method involves using plutonium-239, which absorbs a neutron to become plutonium-240, and with further neutron absorption, it becomes plutonium-241. This isotope then beta decays into americium-241.

Uses

The primary use of americium is in smoke detectors. Americium-241, as an alpha emitter, ionizes air in a smoke detector's ionization chamber, allowing a small and constant current to flow between two electrodes. When smoke enters the chamber, it disrupts this current, triggering the alarm. Americium is also used in industrial gauging devices and in research as a source of neutrons.

Safety

As a radioactive element, americium must be handled with care. It poses both a chemical toxicity hazard similar to other heavy metals and a radiation hazard. Proper safety protocols, including the use of gloves and protective clothing, as well as adherence to regulatory guidelines, are essential when handling americium or equipment containing americium.

See also

• Actinide series
• Radioactivity
• Synthetic elements
• Glenn T. Seaborg