Radioactive Decay
Process in which an isotope’s nucleusCore of an atom, where nearly the entire mass and all positive charge is concentrated. It consists of protons and neutrons. changes (‘decays’) to produce another isotopeOne of two or more atoms with the same atomic number (Z), but different mass (A). For example, hydrogen has three isotopes: H, H (deuterium), and H (tritium). Different isotopes of a given element have different numbers of neutrons in the nucleus.. The original atom is called the ‘parent’ and the resulting atom, the ‘daughter’. There are three modes of radioactive decay:
- Emission of a particle (He nucleus) that decreases the atomic numberA number equivalent to the number of protons in the nucleus of an atom, commonly abbreviated as Z. (Z) by 2 and the atomic weightMass of a neutral atom of a nuclide - also called "atomic weight." The atomic weight of an element is the weighted average of each isotope. (A) by 4 mass units
- Emission of a b particle (electron) that increases Z by 1 and does not change A
- K-electron capture that decreases Z by 1 and does not change A.
The later two processes entail the reaction: 
Some or all content above used with permission from J. H. Wittke.
