Carbon 14 dating example
For example, all carbon atoms have 6 protons, all atoms of nitrogen have 7 protons, and all oxygen atoms have 8 protons.The number of neutrons in the nucleus can vary in any given type of atom.Protons and neutrons make up the center (nucleus) of the atom, and electrons form shells around the nucleus.
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.
Different isotopes tend to concentrate in particular organs: for example, iodine-131 settles in the thyroid gland and can reveal a variety of defects in thyroid functioning.
Another isotope, carbon-14, is useful in studying abnormalities of metabolism that underlie diabetes, gout, anemia, and acromegaly.
In 1961 the isotope carbon-12 was selected to replace oxygen as the standard relative to which the atomic weights of all the other elements are measured.
Carbon-14, which is radioactive, is the isotope used in radiocarbon dating and radiolabeling.
Note that, contrary to a popular misconception, carbon dating is not used to date rocks at millions of years old.