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Nonrenewable Energy: Nuclear
Energy Part 2
What do you know about Nuclear Chemistry?
http://ed.ted.com/lessons/radioactivity-expect-the-unexpected-steve-
weatherall
I. Radiation
• Radiation = any ____________________ through space
Example: electromagnetic radiation
• Not all radiation is dangerous!
o How powerful or dangerous radiation is depends on two
factors: the wavelength and the energy
The _________the ___________, the ______ the _______
• The_______ the _______, the more stuff it can pass
through = the most dangerous!
Example: ______ and ____________have the
____________ so ______________
movement of energy
shorter wavelength higher energy
most dangerous
X-rays Gamma rays most energy
higher energy
• Radiation can be categorized into two groups: nonionizing or
ionizing
• Therefore, _________ radiation is _______________
Nonionizing Ionizing
• ______________ radiation:
radio, microwave, infrared,
visible light, some UV rays
• Causes ___________________
faster or _____________
• ______________ radiation:
some UV rays, X-Ray, Gamma
• Causes ________________
atoms and molecules,
_____________
• Gamma rays can even break up
an atom’s nucleus
Lower energy
molecules to vibrate
give off light
Higher energy
electrons to leave
creating ions
ionizing more dangerous
II. What is Nuclear Chemistry?
• Nuclear Chemistry = The study of reactions that are caused by a
___________________of an atom
• Unlike regular chemical reactions where elements simply re-arrange, in
nuclear reactions ____________are ________!
o _________ in nucleus ________ = ________________
• When a nucleus break ups it releases a lot of energy and that energy is what
is used in nuclear energy sources
o Recall: nuclear energy is a ______________ energy source
While nuclear energy does use elements that can be found in nature,
the element most commonly used in a nuclear power plant (uranium-
235) is very rare and there is a limited amount of it
change in the nucleus
new elements formed
Protons change different element
nonrenewable
Fill in each circle with one of the following:
New element
Ion
Isotope
Molecule/compound
• Why does this happen? Why does the nucleus of an atom change? It
comes down to stability. Some isotopes of elements are stable,
some are unstable
o Nuclear Stability= the larger (more massive) a nucleus is, the
harder it is for it to stay together
• When _______ are __________, they emit energy in the form of
radiation = they are ____________
• When a nucleus is radioactive, it gives off decay particles and
_________________________________in order
_____________________. This process is known as
_____________________________.
isotopes unstable
radioactive
changes from one element to another
to become more stablenatural decay or transmutation
III. Modes of Decay
• Radioactivity (radioactive decay)= the ________________ of the
_________ of an unstable atom in order to become more stable
o Results in the emission or ________ of __________________
• There are different modes or types of decay—different particles that
are released
• Modes of Decay (See Table ___)O
decay or break-up
nucleus
release particles and/or energy
Type of
Decay
Symbol Charge Mass Penetration
Strength
𝟒
𝟐He or
𝟒
𝟐α +𝟐
𝟎
−𝟏e or
𝟎
−𝟏β
𝟎
+𝟏e or
𝟎
+𝟏β
𝟎
𝟎γ
α
alpha
β-
Beta
β+
Positron
γ
Gamma
Rays
-1
+1
0
4
0 (very
little)
0 (very
little)
0 (light
energy)
low
moderate
moderate
high
• Penetration Strength= How far into a material the radioactive
particle will go
o The _________ the particle (less mass), the more it can penetrate
o The more a particle can penetrate, the ________________it is
What is the most dangerous particle?
smaller
more dangerous
gamma rays
IV. Types of Transmutations
• Transmutation = when a ________ decays and _______ into a new and
different nucleus (aka radioactive decay)
1. Natural Transmutation= when an ________ nucleus _______________
breaks up and releases particles and/or energy in order to become more
stable
o Table ___ is a list of isotopes that undergo natural transmutation
Shows what type of particles they release (aka decay mode) and
their half-lives (how long it takes to decay)
nucleus changes
unstable spontaneously
N
Check for Understanding
Table N contains a list of some of the more common radioisotopes, their half-lives, their symbols, and their names. NUCLIDE = an ISOTOPE of a given element
1. Which of the following pairs of nuclides has the same type of radioactive decay mode?
a. K-37 and K-42
b. Fr-220 and Th-232
c. Ne-19 and P-32
d. U-232 and U-235
2. Which of the following radioisotopes will take the longest to decay from 100 g to 50 g?
a. Fe-53
b. Pu-239
c. Th-232
d. N-16
3. Which of the radioisotopes listed
below emits a decay product with a
positive charge?
a. Ra-226
b. Au-198
c. H-3
d. Sr-90
4. Which of the radioisotopes listed
below emits a decay product with the
greatest mass?
a. Co-60
b. C-14
c. Ca-37
d. Fr-220
2. Artificial Transmutation= when a ______ nucleus
gets _____________ or hit by another particle,
producing new elements
o “__________” reaction– doesn’t happen naturally
stable
bombarded
man-made
V. Nuclear Equations
Summary of Types of Reactions
A. Physical Reaction: H2O (s) H2O (l)
Same? Different?
B. Chemical Reaction: 2H2(g) + O2(g) 2H2O (l)
Same? Different?
C. Nuclear Reaction: 167N 0
-1e + 168O
Same? Different?
Compound and mass (and
charge) Phases (s l)
Mass and # of atoms (and
charge)compounds
Mass and charge elements
• As mentioned before, there are two types of decay: natural and artificial
1. Natural Decay - because the process is spontaneous, natural
radioactivity equations always have _____________forming
_______________
o Use Table ___ to identify the type of decay for specific nuclide
o Use Table ___ to identify notation of decay mode
Examples:
1. Francium – 220
2. Gold – 198
3. Neon – 19
two productsone reactant
N
O
4. Iodine– 131
5. Uranium– 233
6. Potassium – 37
How do you balance nuclear equations?
Sum of charges and mass numbers are equal on
both sides
2. Artificial Decay - because artificial transmutation involves a stable
nucleus being “forced” to change, the equation always involves
______________ forming new products
Examples:
1. 94 Be + _____ 126 C + 10 n
2. 2713Al + 42 He 1
0 n + _____
42 He
3015 P
Natural Decay Common to Both Artificial Decay
• ________ nucleus
decays by itself
(___________)
• __ reactant
• Produces
______________
• Mass and charge
conserved
• Both form new
elements
• Both produce
energy
• _______ nucleus
has to get hit to
decay
• __ reactants
• Produces
_______________
two reactants
Unstable
spontaneous
Stable
more energy
1 2
less energy
Check for Understanding
1. Given the reaction:
Which particle is represented by X?
1.
2.
3.
4.
2. Which equation represents a spontaneous transmutation?
1. Ca(s) + 2H2O(ℓ) → Ca(OH)2(aq) + H2(g)
2. 2KClO3(s) → 2KCl(s) + 3O2(g)
3.
4.
VI. Fission and Fusion
• Fission = ________ of a ______ nucleus ____________ nuclei
o ________ neutrons and large amount of ________
o _____________ and _______________ are most commonly used
Example: Fission of Uranium-235 (ANIMATION)
23592U + 10n 92
36Kr + 14156Ba + 3 10n + ENERGY
splitting large into smaller
energy
Uranium-235 plutonium-239
releases
• Fusion = ____________________________nuclei
__________________ one (greater mass)
o Creates _______________________
o ____________ is most commonly used in fusion reactions
Example: Fusion of Hydrogen nuclei
31H + 21H 4
2He + 10n + ENERGY
combining (or fusing) of smaller
to produce a larger
more energy than fission
Hydrogen-1
Nuclear Fission Common to Both Nuclear Fusion
• ___________
nucleus
_____________
particles
• Used to produce
________________
_______
• Produces
_______________
• __________ two
_______ nuclei
together to _______
a _______ one
• Used by _______!
• Produces essentially
_________________
• Both generate
energy the same way
(Convert _____
_______)
____________
___________
electricity in power
plants
radioactive waste
massenergy
Less energy
more energy
the sun
no radioactive waste
Splits larger
into smaller
combines
small form
larger
VII. Half-Life
• Half-Life = ______ it takes for ______ of the original sample of
radioactive nuclei __________
o During one half-life, half of the radioactive nuclei break down and
change into ______________________
o With each additional half-life, the sample keeps “cutting” in half, but
_______________________- all the radioactive nuclei never fully
change into stable nuclei
• The shorter the half-life, the less time an unstable isotope is emitting
radiation before it decays into something more stable and less
dangerous
• The half-life of many radioactive isotopes can be found on Table_____
Equation: 𝑡𝑜𝑡𝑎𝑙 𝑡𝑖𝑚𝑒 𝑝𝑎𝑠𝑠𝑒𝑑
ℎ𝑎𝑙𝑓 𝑙𝑖𝑓𝑒= # of half-lives
N
time half
to decay
new, more stable nuclei
never fully reaches zero
https://www.explorelearning.com/index.cfm?method=cResource.dspDetail&ResourceID=369
Examples:
1. 131I is a radioactive substance used to detect and treat thyroid cancer.
What mass of I-131 remains 24 days after a 2 microgram sample is
administered to a patient?
2. Radon-222 is a carcinogenic house pollutant. How much time must
elapse before 20 grams of radon-222 decays, leaving only 1.25
grams of the original isotope?
3. Based on Reference Table N, what fraction of a radioactive 42K
sample would remain unchanged after 24.7 hours?
4. Based on the graph below, what is the half-life of this substance?
5. What fraction of a sample of cobalt-60 remains radioactive after
3 half-lives?
Uses/benefits
• Dating: Certain radioisotopes with ______________ can be used
to trace the age of substances using their half-life
Examples:
o _______________ can be used to trace the
____________________ (people, plants, animals) because all
living things contain carbon
o ________ can be used to trace the _____________ since
uranium is a natural part of some rocks and has an extremely
long half-life
• Medical: Certain radioisotopes with _______________ can be used
for medical reasons – shorter half-life means they quickly decay into
something stable before they cause harm to the body
Examples:
o Iodine – 131 – used to detect and treat thyroid cancer
o Cobalt – 60 – emits gamma rays that can destroy cancer
o Technetium 99 – detects cancerous tumors
VIII. Uses and Dangers of Nuclear Chemistry
longer half-lives
Carbon – 14 (C-14)
age of any living thing
Uranium age of the Earth
shorter half-lives
Dangers/Risks
• Large amounts of radiation given
off by isotopes can cause
environmental damage and serious
illnesses
• The isotopes used in nuclear power
plants produce waste products that
have _____________ so they
remain radioactive for long periods
of time, making them
___________________________
o accidents can also release
harmful radioactive waste into
air and water
Chernobyl, Ukraine
(1986) (news report)long half-lives
difficult to store and dispose of