Unit 12: Nuclear Chemistry
Name: _________________________
Text Questions from Corwin
1. With regard to nuclear energy, what are two major problems of public concern?
2. Nuclear power makes up about what percentage of the electrical power needs of…
…the world?
…the United States?
…China?
…France?
18.1
3. What does a radioactive element emit?
4. Describe each of the three main types of radiation. Also, include the symbol for each one.
18.2
5. Draw a diagram to show what is indicated by atomic notation. Label each part.
6. What does the term nuclide refer to?
7. How do chemical and nuclear reactions differ?
8. What does a nuclear reaction involve?
9. What two things must be accounted for in writing a balanced nuclear equation?
10. Complete the following, based on Table 18.2.
Particle
alpha, 
beta, –
gamma, 
positron, 
neutron, no
proton, p+
Notation
Mass
11. In beta emission, a neutron decays…
12. Relative to the periodic table, what element is produced in beta emission?
13. A. What effect does gamma emission have on a nuclear equation?
B. Why are gamma rays included in nuclear equations?
14. The term positron comes from a merging of the terms __________ __________, and is an example of
______________.
15. In positron emission, a proton decays…
16. What happens in electron capture?
18.3
17. What is a radioactive decay series?
18. What does the term parent-daughter nuclides refer to?
19. What happens to the atomic number after…
…an alpha emission?
18.4
20. What is meant by the activity of a radioactive sample?
21. What have scientists observed about radioactivity levels?
22. What is the half-life, and what is its symbol?
23. Each time one half-life elapses, the activity…
24. Why is disposing of radioactive waste material a major concern?
18.5
25. What is a radionuclide?
26. The fact that carbon-14 is unstable means what?
…a beta emission?
27. What is the fundamental assumption of radiocarbon dating?
28. Carbon-14 is produced in the upper _____________. ________ rays strike molecules and scatter highenergy _________, which collide with __________; the products are _________ and _________. The
C-14 atoms produced react with __________ to yield radioactive _____, which later becomes
incorporated into plant and animal life.
29. Carbon-14 emits ______ radiation according to the equation…
30. What is the half-life of carbon-14?
31. A. What provides an estimate of the age of very old geological events?
B. What ratio corresponds to one half-life of U-238?
32. How can insect populations be controlled using radiation?
33. What does gamma irradiation do to processed foods?
18.6
34. What happens if a nuclide is bombarded with an atomic particle? What term describes this change?
35. Who discovered the first transmutation reaction, and when?
36. How were the transuranium elements synthesized?
37. Why are linear accelerators and cyclotrons sometimes called “atom smashers”?
18.7
38. What is nuclear fission?
39. List three nuclides that are fissionable (i.e., can undergo fission).
40. What induces the fission process?
41. A. What is released, for each nucleus that undergoes fission?
B. The emitted neutrons can cause…
42. Why is a large mass of the fissionable nuclide needed for a chain reaction to occur?
43. What is the critical mass?
44. Natural uranium is only about _____ fissionable U-235. The rest is nonfissionable _______. To obtain a
chain reaction, it is necessary to __________ the mixture to about _____ U-235.
45. Why is it possible to physically separate 235UF6 and 238UF6 by gaseous diffusion?
18.8
46. What is nuclear fusion?
47. Why is fusion a cleaner process than fission?
48. In terms of nuclear energy, what is the Sun?
49. Why are extreme temperatures needed for nuclear fusion?
50. What is a major practical problem, with regard to using fusion to generate electricity?
51. If used in the generation of energy by fusion, one cubic mile of seawater has more energy than…
Unit 12: Nuclear Chemistry
Name: _________KEY____________
Text Questions from Corwin
1. With regard to nuclear energy, what are two major problems of public concern?
the threat of nuclear accident and the disposal of radioactive waste
2. Nuclear power makes up about what percentage of the electrical power needs of…
…the world?
20%
…the United States?
20%
…China?
…France?
1%
80%
18.1
3. What does a radioactive element emit?
particles and/or energy from an unstable atomic nucleus
4. Describe each of the three main types of radiation. Also, include the symbol for each one.
alpha particle (): a helium nucleus, w/two protons and two neutrons
beta particle (): identical to an electron
gamma ray (): a high-energy photon
18.2
5. Draw a diagram to show what is indicated by atomic notation. Label each part.
A
Sy
Z
A = mass # (p+ + n0); Z = atomic # (p+); Sy = element symbol
6. What does the term nuclide refer to?
the nucleus of a specific atom
7. How do chemical and nuclear reactions differ?
chemical reactions involve valence electrons; nuclear reactions involve atomic nuclei
8. What does a nuclear reaction involve?
a high-energy change in an atomic nucleus
9. What two things must be accounted for in writing a balanced nuclear equation?
atomic numbers and mass numbers (i.e., total charge and total mass)
10. Complete the following, based on Table 18.2.
Particle
alpha, 
beta, –
gamma, 
positron, 
neutron, no
proton, p+
Notation
Mass
11. In beta emission, a neutron decays…
into a proton and releases an electron
12. Relative to the periodic table, what element is produced in beta emission?
the next higher element
13. A. What effect does gamma emission have on a nuclear equation?
no effect
B. Why are gamma rays included in nuclear equations?
to indicate that high-energy radiation is emitted during the decay process
14. The term positron comes from a merging of the terms _positive_ _electron_, and is an example of
_antimatter_.
15. In positron emission, a proton decays…
into a neutron and releases a positron
16. What happens in electron capture?
the nucleus attracts and captures an electron; a proton is converted into a neutron
18.3
17. What is a radioactive decay series?
the stepwise disintegration of a radioactive nuclide until a stable nucleus is reached
18. What does the term parent-daughter nuclides refer to?
a decaying nucleus (the parent) and the resulting nucleus (the daughter)
19. What happens to the atomic number after…
…an alpha emission?
…a beta emission?
decreases by two
increases by one
18.4
20. What is meant by the activity of a radioactive sample?
the number of nuclei that disintegrate in a given period of time
21. What have scientists observed about radioactivity levels?
the levels of radioactivity decrease for all samples over time
22. What is the half-life, and what is its symbol?
the time required for the activity of a sample to decrease by half; t 1/2
23. Each time one half-life elapses, the activity…
drops by 50%
24. Why is disposing of radioactive waste material a major concern?
because dangerous levels of radioactivity can persist for thousands of years
18.5
25. What is a radionuclide?
a nuclide that is unstable
26. The fact that carbon-14 is unstable means what?
that its half-life can be used to estimate the age of any substance containing carbon
27. What is the fundamental assumption of radiocarbon dating?
the amount of C-14 in the atmosphere has remained constant for the last 50,000 years
28. Carbon-14 is produced in the upper _atmosphere_. _Cosmic_ rays strike molecules and scatter highenergy _neutrons_, which collide with _nitrogen_; the products are _carbon-14_ and _protons_. The
C-14 atoms produced react with _oxygen_ to yield radioactive _CO2_, which later becomes
incorporated into plant and animal life.
29. Carbon-14 emits _beta_ radiation according to the equation…
14C

6
30. What is the half-life of carbon-14?
14N
7
+ 0e
–1
5730 years
31. A. What provides an estimate of the age of very old geological events?
B. What ratio corresponds to one half-life of U-238?
the ratio of U-238 to Pb-206
1:1
32. How can insect populations be controlled using radiation?
a bunch of males are sterilized by radiation and released in infested areas; they mate w/females but
no baby bugs result
33. What does gamma irradiation do to processed foods?
destroys microorganisms
18.6
34. What happens if a nuclide is bombarded with an atomic particle? What term describes this change?
the nuclide is converted into a different element
transmutation
35. Who discovered the first transmutation reaction, and when?
Ernest Rutherford; 1919
36. How were the transuranium elements synthesized?
by accelerating a light projectile particle to a high velocity and firing it at a heavy target nucleus
37. Why are linear accelerators and cyclotrons sometimes called “atom smashers”?
because they fire high-velocity projectiles that smash into target nuclides
18.7
38. What is nuclear fission?
the process whereby a heavy nucleus splits into lighter nuclei and releases a large amount of energy
39. List three nuclides that are fissionable (i.e., can undergo fission).
U-235, U-233, and Pu-239
40. What induces the fission process?
a slow-moving neutron
41. A. What is released, for each nucleus that undergoes fission?
B. The emitted neutrons can cause…
two or three neutrons
additional fission reactions (a chain reaction)
42. Why is a large mass of the fissionable nuclide needed for a chain reaction to occur?
atoms are mostly empty space, and neutrons will pass right through the sample if there isn’t enough
43. What is the critical mass?
the minimum mass of fissionable nuclide required to sustain a chain reaction
44. Natural uranium is only about _0.7%_ fissionable U-235. The rest is nonfissionable _U-238_. To obtain
a chain reaction, it is necessary to _enrich_ the mixture to about _3%_ U-235.
45. Why is it possible to physically separate 235UF6 and 238UF6 by gaseous diffusion?
because 235UF6 diffuses slightly faster than 238UF6
18.8
46. What is nuclear fusion?
the process of combining two light nuclei into a heavier nucleus
47. Why is fusion a cleaner process than fission?
it produces very little radioactive waste
48. In terms of nuclear energy, what is the Sun?
a huge fusion reactor
49. Why are extreme temperatures needed for nuclear fusion?
to overcome the strong repulsive forces of the positively-charged nuclei
50. What is a major practical problem, with regard to using fusion to generate electricity?
How to confine a reaction that takes places at millions of degrees
51. If used in the generation of energy by fusion, one cubic mile of seawater has more energy than…
all of the petroleum reserves in the world