On the periodic table, the main product of carbon-14 radioactive decay is nitrogen-14. Carbon-14 undergoes beta-minus decay, converting one neutron into a proton and changing its atomic number from 6 to 7.
Because the number of protons changes, the atom becomes nitrogen rather than remaining carbon. The resulting nitrogen isotope has seven protons and seven neutrons, giving it mass number 14. Carbon-14 has a half-life of about 5,730 years.
Living organisms continually exchange carbon with the environment, including a small amount of carbon-14. After an organism dies, that exchange stops and the carbon-14 gradually decays. Measuring the remaining carbon-14 helps scientists estimate the age of archaeological and biological material. Carbon-14 dating is not the same as dating rocks millions of years old, because its half-life limits its useful range.