Warm Up
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What is nuclear radiation?
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Unit Test Thursday
2/3/2014
Nuclear Radiation
Video
Marie Curie, Nobel Prize Winner
What is Radioactivity?
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When nuclei of unstable isotopes gain stability by
undergoing changes
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These reactions:
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are called nuclear reactions
are always accompanied by the emission of large amounts of
energy
are spontaneous
are not affected by changes in temp, pressure, or presence of
catalysts
cannot be slowed down, speeded up, or turned off
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The process by which atoms emit rays is called
radioactive decay OR nuclear decay
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Unstable nucleus = can be due to the overall size of the
nucleus, having too many or too few neutrons
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Eventually, unstable radioisotopes of one element are
transformed into stable, nonradioactive isotopes of a
different element
3 Types of Radiation
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Alpha particles—positive charge, consists of helium
nuclei (two protons & two neutrons)
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Beta particles—negative charge, consists of fast-moving
electrons formed by the decomposition of a neutron in
an atom
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Gamma rays—no charge, is high energy
electromagnetic radiation given off by a radioisotope, have
no mass, emission of these rays does not alter the atomic
number or mass of an atom
Penetrating Ability
Example
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Uranium-238 releases alpha radiation
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Is transformed into another radioisotope, thorium-234
Example
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Carbon-14 emits a beta particle as it undergoes nuclear
decay, transforming into nitrogen-14
A neutron decomposes into a proton!
Example
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Gamma rays are often emitted along with alpha or beta
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Cobalt-60 shown below
Collaborative Group Work
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Create a study tool:
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On a separate sheet of paper, create a graphic organizer to
compare the three types of radiation.
You should include:
Symbols
 Charge
 Relative mass
 Penetrating power
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Nuclear Reactions Practice
Homework:
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Finish nuclear reactions practice sheet
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Begin studying for unit test by visiting the following site to
review nuclear radiation:
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http://www.mdc.edu/kendall/chmphy/nuclear/types.htm
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You can also watch IsaacsTEACH and review chemistry unit 2
on youtube.
Warm Up
2/4/2014
What is the octet rule? How does an atom of
sodium adhere to the octet rule?
Homework Review
Nuclear Fission & Fusion
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Fusion = when two smaller nuclei combine or fuse
Example = hydrogen + hydrogen  helium (this occurs in
the stars)
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Fission = when a larger nucleus is split into lighter nuclei
Example = atom bomb or nuclear reactors, the splitting
of uranium
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Both types of reactions release large amounts of energy
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Homework
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Watch IsaacsTEACH 2.8 on valence electrons and Lewis
structures (YouTube video)
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Take notes on how to write Lewis structures
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On last week’s homework, add column for Lewis
structures & complete
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Begin to study for your test—review notes, practice
problems completed, IsaacsTEACH videos (2.1-2.9)
Warm Up
2/5/2014
Use the symbols for and distinguish between
alpha particles, beta particles, and gamma rays.
Questions about Unit Test?
Periodic Table
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Mendeleev