1. Nuclear Reactions
Chapter 10

2. Standards
SPS3. Students will distinguish the characteristics and components of radioactivity
SPS3a. Differentiate among alpha and beta particles and gamma radiation.
SPS3b. Differentiate between fission and fusion.
SPS3c. Explain the process half-life as related to radioactive decay.
SPS3d. Describe nuclear energy, its practical application as an alternative energy source, and its potential problems.

3. Nuclear Radiation Radioactive Decay: unstable isotopes emit
particles and release energy to become stable
isotopes.
after radioactive decay, the element changes into a different isotope of the same element or into an entirely different element.

4. Radiation
Nuclear Radiation: particles and energy released from the nucleus during radioactive decay.

5. Types of Radiation 2+ 1- Alpha () -protons and neutrons
paper
Beta-minus (-)
-electrons and positrons 1-
lead
Gamma ()
-high-energy photons
concrete

6. Types of Nuclear Radiation (pg 238)
Radiation Type
Symbol
What is it?
Mass (kg)
Charge
Travel depth through materials
Alpha particle
2 protons and 2 neutrons
6.646x10-27 +2
Least far due to massive size
Beta particle
Fast-moving electrons or positrons
9.109x10-31
-1, (+1)
Farther than alpha, but still not far
Gamma ray
Form of electromagnetic energy
None
Through clothes; Can cause harm
Neutron
A neutron leaving the nucleus
1.675x10-27
Penetrate the farthest

7. Nuclear Decay
Anytime an unstable nucleus emits alpha or beta particles, the number of protons and neutrons changes.
Alpha decay: atomic mass and number change
Beta decay: atomic number changes
Gamma decay: energy of the nucleus is lower, but no change in atomic number or mass

8. Nuclear Decay Why nuclide (nucleus of an isotope) decay…
to obtain a stable ratio of neutrons to protons
Stable
Unstable
(radioactive)

9. + Ra He Rn 226 = 222 + 4 88 = 86 + 2 Alpha Decay
(atomic mass & atomic number change)

10. (atomic mass stays the same; atomic number changes by 1)
Beta Decay Equations 14 6 + C e -1 7
14 =
6 = 7 + (-1)
(atomic mass stays the same; atomic number changes by 1)

11. Actinium-217 decays by releasing an alpha particle
Actinium-217 decays by releasing an alpha particle. Write the equation for this decay process and determine which element is formed.
227 89 + Ac 4 He 2 A Z X

12. Complete the following radioactive-decay equation
Complete the following radioactive-decay equation. Identify the isotope X. Indicate whether alpha or beta decay takes place. 63 28 + Ni e -1 A Z X

13. Radioactive Decay Rates
Half-life: time in which half of a radioactive substance decays; measure of how quickly a substance decays.
-Iodine-131: used by doctors to diagnose medical problems
-Potassium-40: used by geologists to predict the age of rocks

14. Calculating Half-Life
Radium-226 has a half-life of 1599 years. How long will 7/8 of a sample take to decay?
Find out how much will be left.
8/8 - 7/8 = 1/8 left over
2. Calculate how many half-lives until only 1/8 is left. 1
1/2
1/4
1/8
One half life
Two half lives
Three half lives
3. Calculate how many years it will take for 3 half lives to occur.
1599 x 3 = 4797 years

15. Nuclear Fission
Nuclear fission: the process by which a nucleus splits and neutrons and energy are released.
Nuclear chain reaction: a continuous series of fission reactions (pg 340)

16. Nuclear Fusion
Nuclear fusion: when 2 light nuclei combine to form a heavier nuclei
-Hydrogen is turned into Helium on the sun.
(pg 342)

17. Radiation on Earth All around you.
Background radiation: arises naturally from the sun, soil, rocks, and plants
You are exposed to more radiation in the mountains than at sea level

18. Beneficial Uses of Radiation
Smoke detectors release alpha particles
Radiation is used in x rays, MRIs, CT scans, PET scans, and ultrasounds
Radiation therapy is used to treat cancer
Used in agriculture to track the flow of water

19. Nuclear Radiation Risks
High levels of radiation exposure can cause radiation sickness
High concentrations of radon gas can cause cancer

20. Nuclear Power Advantages Disadvantages
Does not produce greenhouse gases
Radioactive products must be handled and stored carefully so they do not escape.
Much more energy available in uranium reserves than gas and coal.
Expensive to build due to many safety regulations.
Waste must be stored in areas away from people, homes, water, earthquakes.