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

Unit #3: Nuclear Processes

What are the 3 types of radioactive decay?

Mr. Heffner 10/5/09

What is radioactive decay?   Radioactive decay is…

  when unstable isotopes transform into more stable isotopes by emitting particles from the nucleus.

shooting out atoms with an neutron inbalance

What is radioactive decay?   There are three types of decay (a.k.a. radiation)

1.  Alpha (α) decay

2.  Beta (β) decay

3.  Gamma (γ) decay

What is an alpha (α) particle?

  Symbol:

  Description:   Basically, a Helium nucleus

  2 protons, 2 neutrons   Atomic mass = 4 amu

  Penetration:   Low, can’t even get through a sheet of paper

He 4 2

What is a beta (β) particle?   Symbol:

  Description:   Basically, an electron

  Neutron converts to a proton

  Penetration:   Medium, can’t get through a sheet of metal

e 0 -1

What is a gamma (γ) particle?

  Symbol:

  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

γ 0 0

Foldable   Make your foldable (9 min)

  Radioactive decay   α particle (symbol, penetration)

  β particle (symbol,penetration)   γ particle (symbol, penetration)   Half-life

  Unstable isotopes   Strong force

  Electrostatic repulsion

Foldable   Review foldable by yourself (4 min)

  MEMORIZE THE SYMBOLS AND DEFINITIONS!

  Quiz your partner (4 min)

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.  α particle

2.  β particle

3.  γ particle

5.  Which of the particles can penetrate a piece of paper? A thin sheet of metal?

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 α, β, and γ particles to become more stable

2.  Which of the following is the correct symbol for a β particle?

a.  42He

b.  01e

c.  0-1e

d.  24He

Exit Slip 3.  An α-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 (γ) rays are a.  high-energy particles that can penetrate skin and

and mutate DNA b.  less energetic than α or β particles

c.  responsible for changing an atom into a different element

d.  not emitted during radioactive decay

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

Homework   Pg. 657 #1

  Pg. 669 #6, 10