- published: 23 Dec 2011
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Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (two protons and two neutrons) and thereby transforms (or 'decays') into an atom with a mass number 4 less and atomic number 2 less. For example:
which can also be written as:
since an alpha particle is the same as a helium-4 nucleus, which has mass number 4 and atomic number 2. It also has a charge +2, but the charge is usually not written in nuclear equations, which describe nuclear reactions without considering the electrons. This convention is not meant to imply that the nuclei necessarily occur in neutral atoms.
Alpha decay is by far the most common form of cluster decay where the parent atom ejects a defined daughter collection of nucleons, leaving another defined product behind (in nuclear fission, a number of different pairs of daughters of approximately equal size are formed). Alpha decay is the most likely cluster decay because of the combined extremely high binding energy and relatively small mass of the helium-4 product nucleus (the alpha particle).
En la penumbra, el patio aúlla
extraños ruidos
soplan las cosas,
si no supiera que el viento
es lo que mueve todo
terminaría muriendo de terror.
Nubes de de angustia
cubren mi cielo
lluvias oscuras de pensamientos,
cuando no quedan salidas
cuando no hay nuevas entradas
cualquier recurso que alivie el dolor
antes de la tormenta.