The document discusses radioactive decay and the three main types: alpha, beta, and gamma decay. It defines each type of particle in terms of its symbol, description, and penetrating power. The key points are that alpha particles have low penetration and are equivalent to helium nuclei, beta particles are equivalent to electrons or positrons and have medium penetration, and gamma rays are high-energy electromagnetic radiation with high penetration.

1. Launch:10/5
 Grab a your binder and immediately take a seat
 Read “Effects of Radiation” handout
 Make a list of at least 5 different effects radiation
has on the human body

2. Unit #3: Nuclear Processes

3. What are the 3 types
of radioactive decay?
Mr. Heffner
10/5/09

4. What is radioactive decay?
 Radioactive decay is…
 when unstable isotopes transform into more stable
isotopes by emitting particles from the nucleus.
atoms with an neutron inbalance
shooting out

5. What is radioactive decay?
 There are three types of decay (a.k.a. radiation)
1. Alpha ( ) decay
2. Beta ( ) decay
3. Gamma ( ) decay

6. What is an alpha ( )
particle?
4
 Symbol:
2
He
 Description:
 Basically, a Helium nucleus
 2 protons, 2 neutrons
 Atomic mass = 4 amu
 Penetration:
 Low, can’t even get through a sheet of paper

7. What is a beta ( ) particle?
0
 Symbol:
-1
e
 Description:
 Basically, an electron
 Neutron converts to a proton
 Penetration:
 Medium, can’t get through a sheet of metal

8. What is a gamma ( )
particle?
 Symbol: 0
0
 Description:
 Basically, a high energy ray
 a.k.a. X-rays
 Penetration:
 High, only stopped by thick wall of lead
 Very dangerous: can penetrate skin  DNA mutation
 Three-eyed fish

9. Foldable
 Make your foldable (9 min)
 Radioactive decay
 particle (symbol, penetration)
 particle (symbol,penetration)
 particle (symbol, penetration)
 Half-life
 Unstable isotopes
 Strong force
 Electrostatic repulsion

10. Foldable
 Review foldable by yourself (4 min)
 MEMORIZE THE SYMBOLS AND DEFINITIONS!
 Quiz your partner (4 min)

11. Practice Questions
1. What happens during radioactive decay?
2. Why does radioactive decay occur?
3. What are the 3 types of decay?
4. Draw the symbol for a(n)
1. particle
2. particle
3. particle
5. Which of the particles can penetrate a piece of
paper? A thin sheet of metal?

12. Exit Slip
1. When an unstable atom undergoes nuclear decay
a. it continues to absorb energy until stability is reached
b. it always changes the identity of the atom
c. it becomes a highly reactive isotope that forms chemical
bonds with other atoms
d. it emits , , and particles to become more stable
2. Which of the following is the correct symbol for a
particle?
a. 42He
b. 01e
c. 0-1e
d. 24He

13. Exit Slip
3. An -particle consists of
a. 2 protons, 2 neutrons, and has an atomic mass of 4
amu
b. a hydrogen-4 nucleus
c. 4 electrons and 2 protons
d. only electrons
4. Gamma ( ) rays are
a. high-energy particles that can penetrate skin and
and mutate DNA
b. less energetic than or particles
c. responsible for changing an atom into a different
element
d. not emitted during radioactive decay

14. Exit Slip
5. A 2-cm thick piece of cardboard placed over a
radiation source would be most effective in
protecting against which type of radiation?
a. alpha
b. beta
c. gamma
d. X-ray

15. Homework
 Pg. 657 #1
 Pg. 669 #6, 10