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.
Protons and neutrons make up the center (nucleus) of the atom, and electrons form shells around the nucleus.
The number of protons in the nucleus of an atom determines the element.
Scientists use a technique called radiometric dating to estimate the ages of rocks, fossils, and the earth.