How is radiactive dating performed
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.
(Creationists claim that argon escape renders age determinations invalid.
However, any escaping argon gas would lead to a determined age younger, not older, than actual.
The two curves cross each other at half life = 1.00.
At this point the fraction of Rb87 = Sr87 = 0.500; at half life = 2.00, Rb87 = 25% and Sr87 = 75%, and so on. 131, Strahler, Science and Earth History: Points are taken from these curves and a plot of fraction Sr-87/Sr-86 (as ordinate) vs. It turns out to be a straight line with a slope of -1.00.
If three different strontium-containing minerals form at the same time in the same magma, each strontium containing mineral will have the same ratios of the different strontium nuclides, since all strontium nuclides behave the same chemically.
Therefore the amount of argon formed provides a direct measurement of the amount of potassium-40 present in the specimen when it was originally formed.