Science, Tech, Math › Science Daughter Isotope Definition - Chemistry Glossary What Is a Daughter Isotope? Share Flipboard Email Print In alpha decay, a parent nucleus decays into a daughter nucleus and an alpha particle. ttsz / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated January 12, 2020 A daughter isotope is the product which remains after an original isotope has undergone radioactive decay. The original isotope is termed the parent isotope. A daughter isotope is also known as a daughter product, daughter nuclide, decay product, or radio-daughter. Example For example, uranium-238 decays along what is called a decay chain: 238U → 234Th → 234mPa → ... → 206Pb Uranium-238 is the parent isotope, while thorium-234, protactinium-234m, and lead-206 are all daughter isotopes. Daughter Isotopes and Half-Life The half-life of an isotope is used to predict the time half of a sample will decay into a daughter isotope, but it cannot predict when an individual atom will decay into a daughter product. However, the nature of the decay product(s) form is highly predictable. Sources Peh, W. C. G. (1996). "The Discovery of Radioactivity and Radium." Singapore Medical Journal. 37 (6): 627–630.