1. 1.4 Whiteboard Review!

2. α β List the two symbols that scientists use to represent a(n)…
Alpha particle?
Beta particle? α β

3. Thorium-230 has a half life of 8000 years
Thorium-230 has a half life of 8000 years. How long will it take a 100 g sample of Th-230 to decay to 25 g?
Find how many half-lives it takes to decay to 25 g. 100  50  25 2 half-lives. 2 x 8000 = 16,000 years

4. Would Phosphorus-32 be stable?
15 protons, 17 neutrons
YES!

5. Mass decreases by 4 amu, Atomic number decreases by 2
When a nucleus undergoes alpha decay, what will happen to the mass? the atomic number?
When a nucleus undergoes beta decay, what happens to the mass? the atomic number?
Mass decreases by 4 amu, Atomic number decreases by 2
Mass doesn’t change, Atomic number increases by 1

6. 1. Identify the type of decay 2. How do you know?
Carbon-14 becomes nitrogen-14
Rn (radon) decays to become Po (polonium)
Lead (Pb) becomes Bismuth (Bi)
Polonium-214 becomes lead-210 β α β α

7. Write the equation for the radioactive decay of the following elements:
Uranium-234 (U, alpha decay)
Bismuth-214 (Bi, beta decay) U
234 92 He 4 2 + Th
230 90 Bi
214 83 e- -1 + Po 84

8. An organism contained 200 grams of Carbon-14 when it died
An organism contained 200 grams of Carbon-14 when it died. After 17,190 years, only 25 grams remain. How long is Carbon-14’s half-life?
Find how many half-lives have passed. 200  100  50  25 3 half-lives 17,190/3 = 5,730 years

9. How many neutrons would a stable isotope of Tin (Sn) have?
58-75

10. Name the 2 forces working in the nucleus of an atom.
Attractive Force: Strong Nuclear Force
Repulsive Force: Electrostatic Force

11. What is the difference between fusion and fission
What is the difference between fusion and fission? Draw a picture showing the difference.
Fusion: combining 2 nuclei, more energy released than fission, stars and hydrogen bomb Fission: splitting a nuclei, energy is released, nuclear powerplants and atomic bombs

12. Write the products of the following fusion reactions:4 2 He 4 2 Be 8 4 +
+ Energy C 12 6 He 4 2 O 16 8 +
+ Energy

13. Write a radioactive decay equation that will produce/make magnesium Using alpha decay - Using beta decay Si 28 14 He 4 2 + Mg 24 12 Na 24 11 e- -1 + Mg 12

14. Ra He + Rn I e- + Xe Radium-222 (Ra, alpha decay)
Iodine-131 (beta decay) Ra
222 88 He 4 2 + Rn
218 86 I
131 53 e- -1 + Xe 54

15. Write a radioactive decay equation that will produce/make Silver-108: - Using alpha decay - Using beta decay In
112 49 He 4 2 + Ag
108 47 Pd
108 46 e- -1 + Ag 47