A helium nucleus emitted by a larger nucleus such as in an atom or uranium during the course of a type of radioactive decay known as alpha decay. Since an atom loses two protons during alpha decay, it changes from one element to another. After undergoing alpha decay, an atom of uranium becomes an atom of thorium. Alpha rays are the least penetrating of all the types of radiation. Jump to top
A helium 4 nucleus (alpha particle) that emerges spontaneously from some heavy nucleus, e.g., plutonium. See; Alpha Particle.
radioactive decay of an atomic nucleaus that is accompanied by the emission of an alpha particle
(click here for animation) Nuclear decay by emission of an alpha particle (4He nucleus ).
The emission of a nucleus of a helium atom from the nucleus of an element, generally of a heavy element, in the process of its radioactive decay.
A type of radioactivity where the nucleus of an atomic of species changes or disintegrates (decays) via an energetic helium ion (alpha particle) being ejected. Alpha decay produces a daughter nucleus of atomic number two less than the parent and of atomic mass number four less than the parent. SEE ALSO beta-minus decay; beta-plus decay; gamma decay; radioactivity.
A form of radioactive decay where a heavy element emits an alpha particle and some energy, thus transforming into a lighter, more stable, element.
Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle through electromagnetic force and transforms into a nucleus with mass number 4 less and atomic number 2 less.