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Title:

Radioactivity

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Radioactivity Radioactivity When an atom of an element has an unstable nucleus, the nucleus can disintegrate, forming subatomic particles and releasing large amounts ... – PowerPoint PPT presentation

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Title: Radioactivity


1
Radioactivity
2
Radioactivity
  • When an atom of an element has an unstable
    nucleus, the nucleus can disintegrate, forming
    subatomic particles and releasing large amounts
    of energy.
  • This release is called radioactivity
  • Alpha and beta particles may be released

3
Alpha Particles
  • An alpha particle is a helium nucleus
  • 2 protons
  • 2 neutrons
  • Symbol is a
  • Mass is 4 amu
  • Charge is 2

4
Beta Particles
  • A beta particle is an electron
  • Symbol is ß
  • Mass is insignificant 0.0006amu
  • Charge is -1

5
Nuclear Reactions
  • During nuclear reactions, an unstable element
    will transform or decay into another element with
    a lower mass
  • In this reaction, an alpha particle has been
    released
  • This is called an alpha decay reaction

6
Nuclear Reactions
  • In the second step of this reaction, an electron
    is released
  • This is a beta decay nuclear reaction
  • It takes 12 more decay reactions to reach a
    stable nuclear structure

7
Gamma Rays
  • Gamma rays are powerful electromagnetic waves
    that are emitted when a nucleus disintegrates
  • They do not transform an unstable element into
    another element or alter its mass

8
Types of Nuclear Reactions
  • Nuclear fission
  • The splitting of a nucleus into two smaller
    nuclei with a tremendous release of energy
  • The energy comes from the mass lost when the
    nucleus is split
  • Often, neutrons are ejected when the nucleus is
    split

9
Types of Nuclear Reactions
  • Nuclear fission

10
Types of Nuclear Reactions
  • Nuclear fusion
  • The combining of two smaller nuclei to form a
    larger single nucleus with a tremendous release
    of energy this energy also comes from lost mass
  • Fusion requires a huge amount of energy and
    pressure
  • Occurs naturally in stars like the sun

11
Types of Nuclear Reactions
  • Nuclear fusion

12
Pros of Nuclear Technology
  • Used in medicine, weapons and electricity
    production
  • Medicine cancer treatments and diagnostic tests
  • Electricity nuclear power plants
  • Produce large amounts of energy
  • Little air pollutio

13
Cons of Nuclear Technology
  • Cooling of electrical plants can result in
    thermal pollution
  • Radioactive leaks possible
  • Fukushima, Japan
  • Three Mile Island
  • Dangerous waste must be stored for long periods
    of time

14
Half-life
  • Radioactive materials decay in a predictable way
  • The rate of decay is called the half-life of a
    substance
  • The half-life is the amount of time it takes half
    of the substance to decay
  • Different substances have different half-lives

15
Half-life
  • For carbon-14 (C-14), the half life is 5370 years
  • If you start with 1000g of C-14, in 5370 years,
    you will have only 500g left (half has decayed)
  • After another 5370 years, you will have 250g
    (half of the 500g)

16
Half-life Activity
  • We are going to use Skittles to simulate what
    happens with atoms of radioactive elements
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