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Radiation and Radioactive Decay

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Geiger Counter. Equipment used to detect radiation by listening to audible clicks. Geiger Counter. Summarize what you just learned! Gamma. Beta. Alpha. What can ... – PowerPoint PPT presentation

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Title: Radiation and Radioactive Decay


1
Radiation andRadioactive Decay
  • Section 4.4 Notes and Sections 25.1-25.2

2
In a Chemical Reaction
  • changes occur to the electrons outside nucleus
  • no change occurs in the nucleus
  • elements involved dont change
  • elements just rearrange themselves to form new
    compounds
  • Example 2 H2 O2 ? 2 H2O

3
In Nuclear Reactions . . .
  • Changes occur in nucleus to number of n0 and p.
  • n0 and p are collectively known as nucleons
  • An unstable atoms nucleus radioactively decays
    into a different, more stable atoms nucleus.
  • Example U-238 ? Th-90
  • This is called transmutation!
  • - radioactive decay process of an unstable
    nucleus emitting radiation to become a different,
    more stable nucleus

4
In Nuclear Reactions . . .
  • radiation includes energy as well as particles
    which are emitted from a radioactive material
  • Radioisotopes undergo radioactive decay and emit
    radiation most often
    in a series of nuclear reactions
    called a radioactive decay series.

5
Discovery of Types of Radiation
6
Types of Radiation
  • Alpha Particles (abbreviated ? )
  • a positively charged particle
  • composed of 2 protons and 2 neutrons which is the
    nucleus of a helium atom
  • represented by the short-hand notation
  • large mass relative to size so it moves slowly
  • low penetration ability through materials because
    it moves so slowly
  • can be blocked by thin, outer layer of our skin
    and paper

7
Types of Radiation
  • Beta Particles (abbreviated ß- )
  • a negatively charged particle
  • composed of a negatively charged electron
  • represented by the short-hand - notation
  • small mass relative to size so it moves fast
  • greater penetration ability than alpha particles
    because they move faster because of their much
    smaller mass
  • can be blocked by metals and protective clothing

8
Types of Radiation
  • Gamma Rays (abbreviated ? )
  • neutral (no charge)
  • composed of little bundles/packets of energy
    called photons
  • represented by the short-hand notation
  • usually emitted with ? and ? particles
  • no mass so it travels at speed of light
  • greatest penetration ability because they move at
    speed of light because of their zero mass
  • can be blocked (but not fully) by lead, really
    thick concrete

9
Radiation Particles and Their Penetration Power
10
Geiger Counter
  • Equipment used to detect radiation by listening
    to audible clicks.

Geiger Counter
11
  • Summarize what you just learned! ?

12
What makes an atoms nucleus UNSTABLE?
  • Stability depends on ratio of n0p
  • The more p a nucleus gets, the more n0 it needs
    to balance out the electrostatic repulsion of p.
  • Too many n0 and p makes the nucleus
    overcrowded like too many people on
    an elevator.
  • So just like if an elevator is overcrowded,
    people have to get off, when a nucleus is
    overcrowded particles must be emitted this is
    radiation!

13
Nuclear Equations
14
Nuclear Equations
Numbers must balance!! Law of Conservation of
Matter must still be obeyed!
15
Nuclear Equations
  • Beta Emission
  • Positron Emission

16
Nuclear Equations
  • Electron Capture

Gamma Emission usually accompanies other types
of decay. Transmutation one element becomes
another.
17
We did it!!!
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