Meaning of carbon dating
For the most accurate work, variations are compensated by means of calibration curves.
They have masses of 13 and 14 respectively and are referred to as "carbon-13" and "carbon-14." If two atoms have equal numbers of protons but differing numbers of neutrons, one is said to be an "isotope" of the other.
At high geomagnetic latitudes, the carbon-14 spreads evenly throughout the atmosphere and reacts with oxygen to form carbon dioxide.
Carbon dioxide also permeates the oceans, dissolving in the water.
When isotopes are to be designated specifically, the chemical symbol is expanded to identify the mass (for example, C is not stable.
As a result it is always undergoing natural radioactive decay while the abundances of the other isotopes are unchanged.