Nuclear Chemistry Review

1. An unstable nucleus ____. a. increases its nuclear mass by fission b. increases its half-life c. emits energy when it decays d. expels all of its protons

2. Ionizing radiation that consists of helium nuclei is ____. a. Alpha Radiation b. Beta Radiation c. Gamma Radiation d. Neutron Radiation

3. type of ionizing radiation can be blocked by a thin piece of metal? a. Alpha Radiation b. Beta Radiation c. Gamma Radiation d. Neutron Radiation

4. If an isotope decays by the process of beta emission, ____. a. the mass number changes b. the atomic number changes c. protons are given off d. Both a & b

5. What particle does argon-39 emit when it decays to potassium-39? a. neutron b. electron c. proton d. alpha particle

6. what element does polonium-208 decay when it emits an alpha particle? Lead-204 Lead-207 Radon-212 Radon-222 Lead-204

7. Controlled nuclear chain reactions ____. a. take place in nuclear reactors b. are always fusion reactions c. never produce radioactive by-products d. are characteristic of atomic bombs

8. Nuclear fusion ____. a. takes place in the sun b. occurs at low temperatures c. can be controlled in the laboratory d. does not exist

9. A reaction that results in the combining of smaller atomic nuclei is called _______. Fission Fusion Bombardment by beta particles A chemical reaction

10. What does increasing neutron absorption accomplish in a nuclear reactor? It speeds up the reaction It can make the reactor explode It slows down the reaction. Trick question, electrons are used in nuclear reactors, not neutrons.

11. Complete the following nuclear reaction: 231, 88 239, 94 238, 91 235, 90

12. If the half-life of a radioactive material is 8 years, how many years will it take for one half of the original amount of material to decay? 4 years 8 years 16 years Need more information

13. After 42 days, 2 g of phosphorus-32 has decayed to 0. 25 g 13. After 42 days, 2 g of phosphorus-32 has decayed to 0.25 g. What is the half-life of phosphorus-32? 14 days 21 days 32 days 10.5 days 2g /2 = 1g 1g /2 = 0.5 g 0.5 g /2 = 0.25 g = 3 times So, 14 days + 14 days + 14 days = 42 days total

14. If the half-life of sodium-24 is 15 hours, how much remains from a 10.0-g sample after 60.0 hours? 160 g 7.5 g 1.5 g 0.63 g 0.63grams

15. Sulfur-34 has a half life of 13. 9 hours 15. Sulfur-34 has a half life of 13.9 hours. If a 15 g sample is left in a beaker for 24 hours, how much sulfur will remain? a. 7.5 g 4.5 g 5.6 g 3.8 g 15 grams /2 = 7.5 grams after 13.9 hours 7.5 grams from 13.9 hours to 24 hours is almost another half life = around 4.5 g

16. How many neutrons are in an alpha particle? 2 3 4 2 Alpha particles are a helium nucleus, which has 2 protons and 2 neutrons

17. What is the approximate ratio of neutrons to protons for stable atoms below atomic number 20? 3 4 1 The number of protons and neutrons are EQUAL for elements #1 (hydrogen) to #20 (calcium)

18. What other particle(s) is involved when Radon-222 produces Polonium-218 and is it through bombardment or decay? Alpha; decay Alpha; bombardment 2 neutrons; decay 2 neutrons; bombardment alpha decay