The illustration below shows the three isotopes of carbon.
Some isotopes of certain elements are unstable; they can spontaneously change into another kind of atom in a process called “radioactive decay.” Since this process presently happens at a known measured rate, scientists attempt to use it like a “clock” to tell how long ago a rock or fossil formed.
Neutrons that come from these fragmented atoms collide with C to be useful in age estimates.
This is a critical assumption in the dating process.
The procedures used are not necessarily in question. The secular (evolutionary) worldview interprets the universe and world to be billions of years old. The use of carbon-14 dating is often misunderstood.
Carbon-14 is mostly used to date once-living things (organic material). Carbon-14 is constantly being added to the atmosphere.
One is for potentially dating fossils (once-living things) using carbon-14 dating, and the other is for dating rocks and the age of the earth using uranium, potassium and other radioactive atoms.
Scientists use a technique called radiometric dating to estimate the ages of rocks, fossils, and the earth.
Many people have been led to believe that radiometric dating methods have proved the earth to be billions of years old.
So, a carbon atom might have six neutrons, or seven, or possibly eight—but it would always have six protons.
An “isotope” is any of several different forms of an element, each having different numbers of neutrons.