How many isotopes (flavors) or carbon are there? Carbon exists in 7 different isotopes. The atomic mass of the isotopes range from 9 amu to 15 amu. The most abundant of these is carbon-12. Next most common isotope is carbon-13. All other carbon isotopes are radioactive. A table is given below showing the isotopes with mass and natural abundance. The half-life and decay mode of the radioactive isotopes are also given. Natural Decay Isotope Abundance Half-Life Mode   C-9 127 msec b +, a C-10 19.3 sec b + C-11 20.3 min b + C-12 98.90% C-13 1.10% C-14 5730 yr b - C-15 2.45 sec b -     Note: b + denotes positron emission b - denotes beta emission   a denotes alpha emission   Carbon-14 is well known as a tool for dating geological and archeological artifacts. It decays to form Nitrogen-14 with a half-life of 5730 yr. It gives reasonably accurate setting for the age of objects between 500 and 50,000 years old.   Carbon-13 is used in magnetic resonance studies of organic molecules.