Matter lesson 8
Half-life and decay chains
OUTCOME
By the end of the lesson you will learn what half life is and be able to use the rule to perform half-life calculations. You will be able to recognise and draw a decay chain.
Reading Quiz 225-127, 133-134
A radioisotope's activity is measured with half-life. A half-lie is the time it takes for 50% of an isotopes nuclei to decay
Most radioactive nuclei go through several decays until they reach a stable isotope.
LEARNING TASKS
Explain and elaborate
Evaluate
Do Questions: 17, 18, 19, 20, 21, 22, 23
Next lesson
You will be performing an experiment to determine the half-life of s radio isotope. Make sure you have:
1. Read through the experiment and watched the videos
2. downloaded excel
3. read the discussion questions
Examine the decay chain for Uranium on page 14. How many decays does Uranium go through before it reaches a stable nuclei? What is that stable nuclei?
In your table group
Thorium 232 decays in the following order:
alpha - beta - beta - alpha - alpha - alpha - alpha - beta - alpha/beta, beta/alpha to finish at Lead 208
Write out the decay equations and create the decay chain