How does carbon 14 dating work? What is an Isotope?

Answer 1

Carbon Dating:
Radiocarbon dating is a radiometric dating method that uses the naturally occurring isotope carbon-14 to determine the age of carbonaceous materials up to ca 60,000 years. Within archaeology it is considered an absolute dating technique. The technique was discovered by Willard Frank Libby and his colleagues in 1949 during his tenure as a professor at the University of Chicago. Libby estimated that the steady state radioactivity concentration of exchangeable 14C would be about 14 disintegrations per minute (dpm) per gram carbon (ca. 230 mBq/g). In 1960, Libby was awarded the Nobel Prize in chemistry for his method to use carbon-14 for age determination.

Isotope:
An isotope is any of several different forms of an element each having different atomic mass. Isotopes of an element have nuclei with the same number of protons (the same atomic number) but different numbers of neutrons. Therefore, isotopes have different mass numbers, which give the total number of nucleons—the number of protons plus neutrons. The term isotope comes from Greek and means "at the same place": all the different isotopes of an element are placed in the same location on the periodic table.

Answer 2

this should help.