Download Nuclear Guided Notes

Name: _________________________________________ Date: __________________ Period: ________
Chapter 21 Notes - Nuclear Chemistry
What is radioactivity?
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Spontaneous emission of radiation when
_______________________________________________________________________________
_______________________________________________________________________________
Background Radiation
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The constant level of radioactivity always present around us
Caused by:
o
o
o
o
What is your radiation exposure? (See Background Radiation Handout)
National average: 500 mrem
Background Average: 360 mrem
Types of Decay
How do nuclear and chemical reactions differ?
The bigger the atom gets and the further from a
_______________________________________________
the less stable the atom is
After element _______________________________
the elements are naturally unstable
and may emit decay particles
What holds the atom together?
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o Force of repulsion between positive charges of the protons in the nucleus
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o Force present that holds quarks together and therefore keeps the protons and neutrons
tightly packed in the nucleus
REVIEW: Types of Decay
Decay Type
Symbol Charge
Reaction Particle
Strength
Stopped by…
Alpha
Beta
Gamma
REVIEW: Nuclear Symbols
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The superscript indicates the mass number and the subscript indicates the atomic number.
𝐴
𝑍𝑋
Steps to Writing Decay Reactions
1. Write the nuclear symbol for the element that is given.
2. Draw an arrow.
3. Identify the type of particle that has decayed and write it after the arrow.
4. Balance the mass number (top) and the atomic number (bottom).
5. Identify the new element.
Alpha Decay
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Examples:
Beta Decay
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Example:
Beta Positive Decay
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Example:
Gamma Decay
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Does it affect the outcome of the reaction?
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Example:
Alpha and gamma decay of:
Half-Life
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The _____________________ of the isotope is what determines the ______________________.
__________________________ = __________________________
Example: After each half life 50% of the sample decays.
Start = 100%
_________ blue particles are present
1 half-life = 50%
_________ blue remain
2 half-lives = 25%
_________ blue remain
3 half-lives = 12.5%
_________ blue remain
4 half-lives = 6.25%
_________blue remain
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After ____________half-lives sample considered nonradioactive because it approaches the level of
background radiation.
Because the amount never reaches zero, radioactive waste disposal and storage causes problems. Would you
want radioactive waste stored in your community?
How can we get rid of nuclear radioactive waste?
Example:
The half-life of mercury-195 is 31 hours. If you start with a sample of 5.00 g, how much of it will still be left after
93 hours?
How many half lives have passed if there is only 1.875 g left of a 30 g sample?
If the half life for this sample is 1 hour, how many total hours have gone by?
Applications:
Where do we see applications of nuclear chemistry every day?
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o
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o
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Exposure to radiation can cause ___________________________________ and ___________________.
What factors affect radiation exposure?
FUSION:
Two light atoms combine to form a heavier atom of higher energy
This reaction powers the ________________!
FISSION:
One heavy atom breaks down into two or more smaller atoms and produces energy
This becomes a ____________________________________________
__________________________: creates a great release of energy (atomic bomb)
Supercritical Fission Reaction:
Particles reacting must have _____________________________:
the minimum amount of mass present for the neutron to hit and react with
________________________________ = _______________________________
How do you control fission reactions?
_____________________________________: used for nuclear power, insert control rods to
absorb released neutrons
Controlled Fission Reaction: (Nuclear Power Plant)