Half life dating formula
It has the same number of protons, otherwise it wouldn't be uranium.
The number of protons in the nucleus of an atom is called its atomic number.
Potassium-Argon dating: The element potassium (symbol K) has three nuclides, K39, K40, and K41. K40 can decay in two different ways: it can break down into either calcium or argon.
The ratio of calcium formed to argon formed is fixed and known.
Radioactive elements "decay" (that is, change into other elements) by "half lives." If a half life is equal to one year, then one half of the radioactive element will have decayed in the first year after the mineral was formed; one half of the remainder will decay in the next year (leaving one-fourth remaining), and so forth.
In old rocks, there will be less potassium present than was required to form the mineral, because some of it has been transmuted to argon.
The carbon-14 undergoes radioactive decay once the plant or animal dies, and measuring the amount of carbon-14 in a sample conveys information about when the plant or animal died.
If you have a fossil, you can tell how old it is by the carbon 14 dating method.
The sum of protons plus neutrons is the mass number.
We designate a specific group of atoms by using the term "nuclide." A nuclide refers to a group of atoms with specified atomic number and mass number.