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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.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.
The ratio of calcium formed to argon formed is fixed and known.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.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.