Problems with radio carbon dating
Isotopes participate in the same chemical reactions but often at differing rates.
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.
Carbon-14 is most abundant in atmospheric carbon dioxide because it is constantly being produced by collisions between nitrogen atoms and cosmic rays at the upper limits of the atmosphere.
Since this rate is slow relative to the movement of carbon through food chains (from plants to animals to bacteria) all carbon in biomass at earth's surface contains atmospheric levels of C is present at atmospheric levels, the molecule must derive from a recent plant product.
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.
Carbon-13 and carbon-14 are thus isotopes of carbon-12.
Along with hydrogen, nitrogen, oxygen, phosphorus, and sulfur, carbon is a building block of biochemical molecules ranging from fats, proteins, and carbohydrates to active substances such as hormones.
All carbon atoms have a nucleus containing six protons.Signals of this kind are often used by chemists studying natural environments.