1. Decay Chains To be able to determine radioactive decay chains

2. An exam question… Potassium decays into argon. The half life of potassium is 1.3 billion years. A sample of rock from Mars is found to contain three argon atoms for every atom of potassium. How old is the rock? (3 marks) The rock must be 2 half lives old – 2.6 billion years

3. Decay chains If Uranium 238 decays via alpha emission, what will the ‘daughter’ atom be? How can we show this? What about if C 14 decays via beta emission? Remember beta emission causes a neutron to turn into a proton. Alpha emission ejects 2 P and 2 N.

4. Try these ones 1.Fr 225 decays via beta emission 2.Pu 239 decays via alpha emission 3.F 20 decays via beta emission 4.Ne 20 decays via alpha emission If mercury underwent beta emission, then the daughter atom underwent alpha emission, what would the product be?

5. An exam question… Potassium decays into argon. The half life of potassium is 1.3 billion years. A sample of rock from Mars is found to contain three argon atoms for every atom of potassium. How old is the rock? (3 marks) The rock must be 2 half lives old – 2.6 billion years