The method was developed by Willard Libby in the late 1940s and soon became a standard tool for archaeologists.
Let's say an atom is missing a neutron or has an extra neutron. An atom is still the same element if it is missing an electron. For example, there are a lot of carbon (C) atoms in the Universe. Atomic masses are calculated by figuring out the amounts of each type of atom and isotope there are in the Universe.Bromine (Br), at atomic number 35, has a greater variety of isotopes. There are two main isotopes at 79 and 81, which average out to the 79.90amu value. While it won't change the average atomic mass, scientists have made bromine isotopes with masses from 68 to 97. As you move to higher atomic numbers in the periodic table, you will probably find even more isotopes for each element.If we look at the C-14 atom one more time, we find that C-14 does not last forever.2) To familiarize students with the concept of half-life in radioactive decay.3) To have students see that individual runs of statistical processes are less predictable than the average of many runs (or that runs with relatively small numbers involved are less dependable than runs with many numbers).