Carbon dating radioactive
Note that, contrary to a popular misconception, carbon dating is not used to date rocks at millions of years old.
Before we get into the details of how radiometric dating methods are used, we need to review some preliminary concepts from chemistry.
Atomic mass is a combination of the number of protons and neutrons in the nucleus.
So, a carbon atom might have six neutrons, or seven, or possibly eight—but it would always have six protons.