3.5 Review and Reinforce Science

Take Our Quizzes.

Log in Sign up. How can we help? What is your email? Upgrade to remove ads. Scientists use the amount of radioactive isotopes found in rocks and fossils to calculate the ages of the rocks and fossils. This process is called. It changes one element into another element. The spontaneous emission of radiation by an unstable atomic nucleus is called.

Half of the radioactive atoms in a sample of sodium will decay in 15 hours. Fifteen hours is the of sodium