proton number , and the element symbol Note: Input the symbol of the element, not the name of the element. 228 Ra → 88 -1 Question 14 228 Ra → e 88 -1 Suppose, if the nuclei in this radioactive process decayed differently and emitted a positive charge e instead of negative (and also decays to a different element), the emitted particle is an electron a proton a neutron O a positron

238 2U undergoes a series of reactions in which it emits eight He nuclei and six elections. Which isotope results from this series of reactions? 206TI 206 82 Pb 207 82 o 2 Ra

3C. Write the equation for the beta-positive decay of Potassium-40. b) Write the element that is formed in the beta-positive decay of Potassium- 40. Your answer

Madame Curie filled glass vials with pure radon, produced by her radium, for use in hospitals. Radon has a short half-life of 3.8 days. Suppose that she put 1 MBq of radon in a vial. i) Sketch a graph of the activity of the radon over the next week or two. Label the axes with appropriate numbers and units. Mark on the graph the half-life and the characteristic time. ii) Radon decays through a chain of four very short-lived radionuclides (halflives of 20 minutes and less) before reaching a relatively stable isotope of lead. Approximately what activity will the vial have two or three hours after filling, and about two weeks after filling?