Parent and Daughter Nuclide
The nuclide undergoing decay and the nuclide produced by that decay.
Formula / equation
parent → daughter + radiation
Unit
Dimensionless
In depth
The daughter may itself be radioactive, in which case decay continues down a chain until a stable nuclide is reached. Measuring the accumulated ratio of daughter to parent in a closed sample is the basis of all radiometric dating.
Examples in the real world
Radium-226 as the parent of radon-222; potassium-40 as the parent of argon-40 in mineral dating.