Because it's a statistical measurement, there's always a margin of error in the age figure, but if the procedure is done properly, the margin is very small. We must know the original quantity of the parent isotope in order to date our sample radiometrically. In order to do so, we need an isotope that's part of a mineral compound. Because there's a basic law of chemistry that says "Chemical processes like those that form minerals can't distinguish between different isotopes of the same element." This is because an element's chemical behavior depends only on the number of electrons it has, which is the same as its number of protons.
Radioactive dating is also called
If an element has more than one isotope present, and a mineral forms in a magma melt that includes that element, the element's different isotopes 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. Well, an atom's chemical activity pattern is a result of its electron shell structure.
So, if we know how much of the isotope was originally present, and how much there is now, we can easily calculate how long it would take for the missing amount to decay, and therefore how long it's been since that particular sample was formed.
That's the essence of radiometric dating: measure the amount that's present, calculate how much is missing, and figure out how long it would take for that quantity of the isotope to break down.
Contents: The half-life of a radioactive isotope is defined as the time it takes half of a sample of the element to decay.
A mathematical formula can be used to calculate the half-life from the number of breakdowns per second in a sample of the isotope.
Radiocarbon dating does not work on anything inorganic, like rocks or fossils.
Only things that once were alive and now are dead: bones, teeth, flesh, leaves, etc.
So the dates derived from C14 decay had to be revised.