Radio active dating isotop
If we knew the fraction of a radioactive element still remaining in a mineral, it would be a simple matter to calculate its age by the formula To determine the fraction still remaining, we must know both the amount now present and also the amount present when the mineral was formed.Contrary to creationist claims, it is possible to make that determination, as the following will explain: By way of background, all atoms of a given element have the same number of protons in the nucleus; however, the number of neutrons in the nucleus can vary.Strontium-86 is a stable element that does not undergo radioactive change.In addition, it is not formed as the result of a radioactive decay process.
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.
Rubidium-Strontium dating: The nuclide rubidium-87 decays, with a half life of 48.8 billion years, to strontium-87.
Strontium-87 is a stable element; it does not undergo further radioactive decay.
Any argon present in a mineral containing potassium-40 must have been formed as the result of radioactive decay.
F, the fraction of K40 remaining, is equal to the amount of potassium-40 in the sample, divided by the sum of potassium-40 in the sample plus the calculated amount of potassium required to produce the amount of argon found. In spite of the fact that it is a gas, the argon is trapped in the mineral and can't escape.