1. This is a modified true/false formative assessment. Each statement you read will be either true (T), or false (F). If true, simple write a T, if false, write an F, followed by the word or phrase which will correct the underlined portion of the sentence. Example: In order to accurately find an actual date for a substance, geologists use relative dating techniques. Answer: F; radiometric

2. 1.The radioactive isotope in a sample is known as the parent, while the stable element it breaks down into is the daughter. 2. The rate of decay is measured in units called half- lives, and it is the amount of time it takes for ½ of the daughter to evolve. 3. If the half-life of 226 Ra is 1,500 years, and there are 10 grams of radium in the original sample, after 3,000 years, 5 grams or radium will remain.

3. 4.When U-235 decays, units of protons and neutrons bound together are emitted from the nucleus in a process known as beta decay, which results in the formation of lead. 5.Radiocarbon dating uses the unstable 14 C isotope, which decays to the stable 12 C. ***BONUS*** Describe briefly why it would be impossible to determine the age of fossilized dinosaur bones using 14 C method.