Radioactive dating u 238
Every radionuclide has a specific decay rate, which is measured in terms of "half-life." Radioactive half-life is the time required for half of the radioactive atoms present to decay.
Some radionuclides have half-lives of mere seconds, but others have half-lives of hundreds or millions or billions of years.
The discovery of the radioactive properties of uranium in 1896 by Henri Becquerel subsequently revolutionized the way scientists measured the age of artifacts and supported the theory that the earth was considerably older than what some scientists believed.
Those that decay in more than one step are called series radionuclides.
The series of decay products created to reach this balance is called the decay chain The series of decays or transformations that radionuclides go through before reaching a stable form. The decay products within the chain are always radioactive.
Elements in the periodic table can take on several forms.
Some of these forms are stable; other forms are unstable.