This decay mode relieves the nucleus of two units of positive charge (two protons) and four units of mass (two protons two neutrons).
The decay continues until, finally, after a total of 14 steps, Pb-206 is produced.
Pb-206 is stable, and the decay sequence, or series, stops.
An alpha particle is composed of two protons and two neutrons, so it can be represented as a Helium-4 atom.
As an alpha particle breaks away from the nucleus of a radioactive atom, it has no electrons, so it has a 2 charge.
Radioactivity, also known as radioactive decay, is a process by which a radioactive isotope loses subatomic particles (helium nuclei or electrons) from its nucleus along with usual emission of gamma radiation, and becomes a different element.
In a large collection of atoms, there is a definite time, called the half-life of the isotope, after which one-half of the total number of nuclei would have decayed.
Though still heavily used, relative dating is now augmented by several modern dating techniques.
Radiocarbon dating involves determining the age of an ancient fossil or specimen by measuring its carbon-14 content.
Radon-222 (Rn-222) is another alpha particle emitter, as shown in the following equation: Here, Radon-222 undergoes nuclear decay with the release of an alpha particle.
The other remaining isotope must have a mass number of 218 (222 – 4) and an atomic number of 84 (86 – 2), which identifies the element as Polonium (Po).
Carbon-14 has a half-life of 5,730 ± 40 years, meaning that every 5,700 years or so the object loses half its carbon-14.