1. RADIOACTIVITY EQUATIONS : QUIZ 3 You will need paper to write down your answers to the questions. You can then check your answers against those provided at the end.

2. QUESTION 1a: What is a beta particle? [1] QUESTION 1b: Caesium (Cs) decays to barium (Ba) by the emission of a beta particle. If the caesium has a mass number of 137 and a proton number of 55, write an equation to represent the decay.[4] Click again for a hint! Hint: use 0 e to represent the beta particle. -1 and remember, mass must be conserved You should not need more than 10 minutes to answer all the questions in this quiz.

3. a) What is an alpha particle composed of? [1] b) What is the mass number and the proton number of an alpha particle? [2] QUESTION 2 c) Element X has 98 protons and 94 neutrons in its nucleus and decays to element Y by the emission of an alpha particle. Write an equation to illustrate this. [4] Click again for a hint. X Y +  … Now fill in the mass and proton numbers

4. The equations below represent the radioactive decay of various radionuclides. The particle of radiation is represented by an ‘x’. Look carefully at the equations and determine what type of particle ‘x’ represents in each case. QUESTION 3 : last question a) 226 Ra 222 Rn + x [1] 88 86 b) 137 Cs 137 Ba + x [1] 55 56 c) 40 Rs 36 Po + x [1] 27 25

5. ANSWERS : Credit yourself with marks as suggested. Words in brackets help to make your ideas clearer (but are not necessary for the mark). Words that have been underlined must be used in your answer to get the mark.

6. a) A beta particle is a (fast-moving) electron. [1] Question 1 b) 137 Cs 137 Ba + 0 e 55 56 -1 1 mark for having 1 1 1 for 137 and 55 in the remembering the right places symbol for an electron

7. a) Two protons and two neutrons [1] b) an alpha particle has a mass number of 4 [1] and a proton number of 2 [1] QUESTION 2 c) 192 X 188 Y + 4  98 96 2 Marks will be credited for writing the proton number (98) in the right place, 1 mark for calculating and writing in the correct mass number (98+ 94 =192). One mark for the correct mass and proton numbers of element Y [1] [1] [1] [1]

8. Whenever radioactive decay occurs, the total mass must always be conserved. If you add up the numbers at the top (representing the mass number) you should get the same number on both sides of the equation. The same applies for the proton numbers (the numbers to the bottom left). QUESTION 3 : last question a) 226 Ra 222 Rn + x 88 86 b) 137 Cs 137 Ba + x 55 56 c) 40 Rs 36 Po + x 27 25 ‘x’ is an alpha particle..[1] ‘x’ is a beta particle..[1] ‘x’ is an alpha particle..[1]

9. Make sure that you keep a record of your answers and your total score. It is especially important that you take note of which questions you got wrong.