When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.Isotopes are important to geologists because each radioactive element decays at a constant rate, which is unique to that element.This technique relies on the property of half-life.Half-life is defined as the time it takes for one-half of a radioactive element to decay into a daughter isotope.Alpha particles are positively charged, beta particles are negatively charged, and gamma particles have no charge.The radiations also have increasing levels of energy, first Alpha, then Beta, and finally Gamma, which is the most energetic of all these. When a radioactive nucleus changes, the remaining nucleus (and atom) is not the same as it was. The term half-life describes the time it takes for half of the atoms in a sample to change, and half to remain the same.The atoms of some chemical elements have different forms, called isotopes.
Also called absolute dating, scientists use the decay of radioactive elements within the fossils or the rocks around the fossils to determine the age of the organism that was preserved.For carbon, there are a lot of C-12, a couple of C-13, and a few C-14 atoms.When you average out all of the masses, you get a number that is a little bit higher than 12 (the weight of a C-12 atom). If you have looked at a periodic table, you may have noticed that the atomic mass of an element is rarely an even number. If you are an atom with an extra electron, it's no big deal. As you learn more about chemistry, you will probably hear about carbon-14. C-14 is considered an isotope of the element carbon.