Explain how radioactive dating works
Since all atoms of the same element have the same number of protons, different nuclides of an element differ in the number of neutrons they contain.For example, hydrogen-1 and hydrogen-2 are both nuclides of the element hydrogen, but hydrogen-1's nucleus contains only a proton, while hydrogen-2's nucleus contains a proton and a neutron.The mass number doesnt change, while the atomic number goes down by 1.So an atom of potassium-40 (K40), atomic number 19 can absorb an electron to become an atom of argon-40 (Ar40), atomic number 18.Radiometric dating methods are the strongest direct evidence that geologists have for the age of the Earth.All these methods point to Earth being very, very old -- several billions of years old.Thats the essence of radiometric dating: measure the amount thats present, calculate how much is missing, and Obviously, the major question here is "how much of the nuclide was originally present in our sample? If an element has more than one nuclide present, and a mineral forms in a magma melt that includes that element, the elements different nuclides will appear in the mineral in precisely the same ratio that they occurred in the environment where and when the mineral was formed. The third and final axiom is that when an atom undergoes radioactive decay, its internal structure and also its chemical behavior change.Losing or gaining atomic number puts the atom in a different row of the periodic table, and elements in different rows behave in different ways. C14 is radioactive, with a half-life of 5730 years.
In other words, electron absorption is the exact reverse of beta decay.
The decay rate and therefore the half-life are fixed characteristics of a nuclide. Thats the first axiom of radiometric dating techniques: the half-life of a given nuclide is a constant.
(Note that this doesnt mean the half-life of an element is a constant.
Uraniums abbreviation is U, so uranium-238 can be more briefly written as U238.
Many nuclides are stable -- they will always remain as they are unless some external force changes them.
In alpha decay, the radioactive atom emits an alpha particle.