1. Determine the products of nuclear transformations and use the abbreviated notation for transformation reactions.
2. Predict the product resulting from neutron capture by a given isotope, which is then followed by beta decay.

Artificial Radioactivity. Nuclear transmutation is the process of converting one element into another. Artificial radioactivity results when an unstable nucleus is produced by transmutation. Irene Curie and Frederic Joliot discovered this phenomenon in 1933 while bombarding light elements with a particles from radioactive sources. For example, when aluminum atoms are bombarded with alpha particles the product is phosphorus-30 which is radioactive. Phosphorus-30 decays by positron emission and has a half-life of 2.5 min. It does not occur naturally in phorphorus compounds.

Neutrons readily produce "artificial" radioactivity because they are easily captured by stable nuclei, with the result that a new nucleus is formed that has a higher n : p ratio. This leads to a product that decays by beta decay. Neutron capture by chlorine-37 yields chlorine-38.

Chlorine-38 has a short half-life, and is not found naturally on Earth. Note that capture of a neutron, followed by beta decay, yields a new element (Ar) with an atomic number one greater than the original element. This procedure of neutron capture followed by beta decay of the product nucleus has been used to synthesize elements that were "missing" from the periodic table, such as Tc and Pm, elements number 43 and 61, respectively. All isotopes of these elements are radioactive.

Using neutrons as bombarding particles is convenient because neutrons have no charge and therefore are not repelled by target nuclei. When projectiles are positively charged such as protons and alpha particles, they must have considerable kinetic energy in order to overcome the electrostatic repulsion as these particles approach and collide with the target nucleus.

Nuclear transmutation processes can be abbreviated according to the following format.

Target nucleus (bombarding particle, ejected particle) Product nucleus

The alpha bombardment reaction above can be written:

The symbols n, p, d, a, e, and g are used in this notation to represent neutron, proton, deuteron, alpha particle, electron, and gamma ray.