Name______
Chapter 10 Nuclear Changes
Section 1: What Is Radioactivity? - Read pages 327-336 in your book and answer the following questions.
1. Write in the blank the term that matches each description:
beta particles alpha particles neutron emission gamma rays
______a. helium-4 nuclei
______b. high-energy electromagnetic radiation emitted by a nucleus
______c. electrons emitted by neutrons decaying into an unstable nucleus
______d. release of high-energy neutrons
2. Determine the amount of time it takes for 96.0 of a radioactive sample of an isotope of bromine to decay to 24.0. The half-life of the isotope is 16.5 hours.
a.
b.
total # of half-lives = ______
c.
3. Determine the half-life of a radioactive substance that has changed through radioactive decay. After 40 days, the original substance left is 1/16 of the original amount.
a.
b.
total # of half-lives = ______
c.
4. Identify which of the following is true for gamma ray emission.
a. The atomic number increases but the atomic mass stays the same.
b. Both the atomic number and the atomic mass remain the same.
c. The atomic number decreases and the atomic mass increases.
d. The atomic number stays the same and the atomic mass decreases.
5. Describe what happens when beta decay occurs (p 330).
______
6. How it is possible for negatively charged beta particles to be emitted from a positively charged nucleus during nuclear decay? (p 329)
______
______
**BONUS** Answer correctly for bonus on your homework grade.
7. Explain why charged particles do not penetrate matter deeply.
______
Name______
Chapter 10 Nuclear Changes
Section 2: Nuclear Fission and Fusion - Read pages 337 to 342 and answer the following questions.
1.Write in the blank the term that matches each definition.
critical mass fusion reaction strong nuclear force
______a. attractive force that acts between protons and neutrons at very
short distances
______b. joining of two lighter nuclei to form a heavier nuclei
______c. the minimum amount of a fissionable isotope that can sustain a
nuclear chain reaction
2. Describe how a fission reaction is started (p 340).
______
3. Explain why the energy associated with even a small mass is immense. (Hint: Consider the way c appears in the mass-energy equation - p 339)
______
4. Strong nuclear forces affect a nucleus by:
- making it unstable
- holding protons and neutrons together
- creating decay
- destroying the electrons
5. Explain why most isotopes of elements that have a high atomic number are radioactive (Remember, atomic # = # of protons! - p 338).
______
**BONUS - Answer correctly for bonus on your homework grade!**
6. A nucleus captures two neutrons and decays to produce one neutron. Is this process likely to produce a chain reaction? Explain why or why not.
______
______
Name______
Chapter 10 Nuclear Changes
Section 3: Nuclear Radiation Today – Read pages 344 to 351 of your book and answer the following questions.
1. People receive some natural or background radiation exposure each day from:
a. the sun.
b. household appliances such as television sets and microwave ovens.
c. medical and dental X rays.
d. All of the above
2. Determine whether the following statements are true or false.
_____ a. The longer a person is exposed to radiation and the closer the person is to the radiation, the greater the
risk.
_____ b. Radiation cannot be detected by our sense of sight, smell, taste, hearing, or touch.
_____ c. Nuclear fission is dangerous because it produces gaseous pollutants.
3. Explain why ventilation is very important if there is a risk of exposure to radon gas in your home or school (p 348).
______
4. Name the nuclear radiation(s) that can be easily stopped by skin or clothes (p 348).
a. ______
b. ______
c. ______
5. Explain ionization. Which forms of nuclear radiation are capable of ionizing matter? (p 348)
______
6. Explain one way nuclear radiation is used in the field of medicine (p 346).
______
7. Identify three activities that add to background radiation under normal circumstances (Figure 1)
- ______
- ______
- ______
8. Describe how smoke detectors use alpha particles and what sets off the alarm (p 346).
______
______
9. Explain how radioactive tracers help locate tumors (p 346).
______
______
**BONUS - Answer correctly for bonus on your homework grade!**
10. Describe three factors that contribute to how much damage is done to living tissue by radiation.
______
______