Although the time at which any individual atom will decay cannot be forecast, the time in which any given percentage of a sample will decay can be calculated to varying degrees of accuracy.The time that it takes for half of a sample to decay is known as the half life of the isotope.
Radioactive elements "decay" that is, change into other elements by "half lives.
The half-life of a radioactive isotope describes the amount of time that it takes half of the isotope in a sample to decay. Plus, get practice tests, quizzes, and personalized coaching to help you succeed. However, rocks and other objects in nature do not give off such obvious clues about how long they have been around.
Radiometric dating involves dating rocks or other objects by measuring the extent to which different radioactive isotopes or nuclei have decayed.
When we speak of the element Carbon, we most often refer to the most naturally abundant stable isotope 12 C.
Although 12 C is definitely essential to life, its unstable sister isotope 14 C has become of extreme importance to the science world.
Cloth wrappings from a mummified bull Samples taken from a pyramid in Dashur, Egypt.