Nuclear Chemistry or Radiochemistrv
-Know basic vocabulary
-2 types of transmutations
-4 nuclear decay emissions
-Write nuclear decay reactions
-Calculate y^ lives
-know how nuclear powerplants work
-Know about Chernobyl
-Be able to complete the U-238 decay series
Vocabulary
Terms
Mass defect
Transmutation
Binding energy
Half-life
Fission
Fusion
Alpha particle
Beta particle
Positron
Radioactive decay
Gamma rays
Geiger counter
Radioisotope
Band of stability
Nucleon
Nuclide
Ionizing radiation
Chain reaction
Radiotracer
Responses
Definitions
The difference between the actual mass of an atom and the sum of
the masses of the isolated particles composing it
The conversion of one element into another; may be natural or
artificial
The energy required to split the nucleus into separate nucleons
The length of time necessary for one-half an amount of a
radioactive nuclide to disintegrate
The splitting of an atomic nucleus into smaller fragments,
accompanied by the release of neutrons and a large amount of
energy
A nuclear reaction in which small nuclei are combined to make a
larger nucleus, accompanied by the release of a large amount of
energy
A helium nucleus, containing two protons and two neutrons
A fast moving electron emitted from certain radioactive nuclei; it is
formed when a neutron decomposes
A particle that has the same mass as an electron but has a positive
charge
The process in which an unstable nucleus loses energy by emitting
radiation
A quantum of energy of very high frequency and very short
wavelength
A gas-filled metal tube used to detect the presence of beta radiation
Isotopes that have unstable nuclei and undergo radioactive decay
The location of stable nuclei on a neutron-vs.-proton plot
A particle found in the nucleus of an atom; a proton or a neutron
An atom of a specific energy with a specified number of protons
and a specified number of neutrons in its nucleus
Radiation which has enough energy to produce ions by knocking
electrons off some of the atoms it strikes
A self-sustaining fission process caused by the production of
neutrons that proceed to split other nuclei
A radioactive nuclide, introduced into an organism for diagnostic
purposes, whose pathway can be traced by monitoring its
radioactivity
Nuclides (I)
Nuclide
Helium-4
Atomic#
#Protons
#Electrons
#Neutrons
2
14
Carbon Boron - 11
Mass#
5
29
Silicon -
15
Copper -63
42
Arsenic -75
Bromine -
79
Gold -197
86
Radon-222
238
Uranium Neon-22
45
80
146
10
35
Copper - 64
Lithium-
6
3
Hyphen
notation
Nuclear
notation
i^jl
Name
Types of Nuclear Decay
. . . A nuclear reaction is a reaction that affects the
^'^
^
of an atom.
. . . A transmutation is a change in the identity of a nucleus as a result of a change in the number of its
.
. . . Radioactive decay is the spontaneous disintegration of a nucleus into a slightly lighter nucleus, accompanied by emission
of
,
, or both.
Nuclear change or decay is an
process. The stability of a nuclide partly depends on the relative number of
and
it contains. In some cases, having too many neutrons is the cause of the
. Stable nuclides
are recognized experimentally because they do not change. Unstable nuclides
in order to reach stability.
Changing to a stable nuclide may involve one or more decays.
In nuclear decay, the initial nucleus is called the
, and the nev^ nucleus that results is called the
.
Nuclear equations representing a nuclear reaction are balanced when the sum of the atomic numbers on the right is equal
to the
on the left. Sums of the
numbers on the right and left sides must be equal also.
Nuclear Decay Organizer and Nuclear Equation Practice
Alpha Particle
Emission
Symbol
Beta Particle Emission
2He or |a
How It changes the
nucleus...
>
Gamma Ray Emission
Positron Particle
Emission
or_?^
.IP
...Decreases the
mass number by 4
. . .Converts a
neutron into a proton
. . .Converts a proton
into a neutron.
. . . Decreases the
atomic # by 2
. . .Increases atomic #
by 1
. . . Atomic #
decreases by 1; mass
# stays same
. . .No change to the
nucleus
Examples of Nuclear Decay Processes
p
a emission
^llU
tHe
+
p * emission
emission
^tTh
1.
\Nr\te an equation to represent the decay of radium-226 by a emission and bismuth-209 by 3^ emission.
2.
The products from a nuclear reaction are an a particle and polonium-218. Identify the parent nuclide and write equation.
3.
Write equations for the decay of and radium-224 by a emission.
4.
Write equations for the decay of cobalt-60 and calcium-39 by P emission.
5.
Write an equation for the decay of copper-64 and nitrogen-12 by p'^emission.
6.
Fill in the correct symbol to complete each equation.
a) ^^2U ^
c)
'llRa
?
+2^6
-> 'llRn
b) mm
+
?
d) f.K
^
^
?
_?e
t|]Ca + ?
7.
Write an equation for the decay of polonium-218 by a emission.
8.
Write an equation for the decay of carbon-14 by p" emission. Then by P * emission.
Table O
Symbols Used in Nuclear Chemistry
Notation
Symbol
alpha particle
l l i e or | a
a
beta particle
_','<•
r
Name
gamma radiation
?,Y
neutron
proton
positron
Y
n
|TI <>,- {p
P
1^"
Name
Per
Nuclear Decay
Using a periodic table, fill in the blanks to complete the following nuclear equations. Then, identify
which type(s) of decay particles were produced.
Standard: Students know the three most common forms of radioactive decay (alpha, beta, and
gamma) and know how the nucleus changes in each type of decay.
Describe the change that took place above.
Describe the change that took place above.
Describe the change that took place above.
6 ^
^
+
7iV
Describe the change that took place above.
Describe the change that took place above.
Describe the change that took place above.
Describe the change that took place above.
'i'c
+ ; / /
^
+
Describe the change that took place above.
„ V
CD
05
>
<
CD
£
£
CD
Nuclear Chemistry Worksheet
Using your knowledge of nuclear chemistry, write the equations
processes:
for the following
1)
The alpha decay of radon-198
2)
The beta decay of uranium-237
3)
Positron emission from silicon-26
4)
Sodium-22 undergoes electron capture
5)
What is the difference between nuclear fusion and nuclear fission?
6)
What is a "mass defect" and why is it important?
7)
Name three uses for nuclear reactions.
For chemistry help, visit www. chem fiesta, com
©2003 Cavalcade Publishing-
All Rights
Reserved
Nuclear Chemistry Worksheet - Solutions
Using your knowledge
processes:
of nuclear chemistry, write the equations
for the following
1)
The alpha decay of radon-198
2)
The beta decay of uranium -237
3)
Positron emission from silicon-26
4)
Sodium-22 undergoes electron capture
5)
What is the difference between nuclear fusion and nuclear fission?
In nuclear fusion, small nuclei are combined to form a larger nucleus
" this process releases a very large amount of energy, and is the
main source of energy in the sun. In nuclear fission, large nuclei
break apart to form smaller ones, releasing a large amount of energy.
Fission is used in nuclear power plants to generate energy.
6)
What is a "mass defect" and why is it important?
"Mass defect" refers to the difference between the mass of the
nucleons (protons + neutrons) in a nucleus when weighed separately
and the mass of the nucleus when it's put together. This difference
is important because this missing mass is converted to energy using
E=mc^ that's used to hold the nucleus together.
7)
Name three uses for nuclear reactions.
•
•
•
Nuclear weapons
Medicine
Nuclear power generation
For chemistry help, visit www. chemfiesta. com
©2003 Cavalcade Publishing-
All Rights
Reserved
Name
pd
2009
Half-Life
In a sample of radioactive nuclides, the decay of an individual nuclide is a
event. It is impossible to predict which
nucleus will be the next one to undergo a nuclear change. How, then, do you make sense out of things that cannot be predicted on an
individual basis? One approach is to predict change for a given amount of a very large number of nuclei —for example, one half.
Scientists commonly discuss radioactive decay in terms of half-life. The
it tal<es for one half of the parent nuclides in a
radioactive sample to decay is known as its half-life.
The half-life of fluorine-21 is approximately five seconds. If a sample of fluorine-21 contains one million atoms, then 500 000 of the
nuclei will decay within five seconds. Within another five seconds, 250 000 additional nuclei (one half of those remaining) will decay,
and so on. Many radioactive nuclei have much longer half-lives. A sample of one million nuclei of strontium-90 will decay much more
slowly because the half-life of strontium-90 is about 29 years. Half -lives may be used calculate the fraction of parent nuclides that
remain after a certain amount of time.
Helpful Hints!!
(Use your y" button or x^); n = total time / Vz life time; n = # of >i lives that have occurred; mass remaining = mass x Vz
Sample calculation:
Fluorine-21 has a half-life of approximately 5 seconds. What fraction of the original nuclei would remain after 1 minute?
If you began with 42 grams of fluorine, how many grams of fluorine would remain?
9.
lodine-131 has a half-life of 8 days. What fraction of the original sample would remain at the end of 32 days?
10. The half-life of chromium-51 is 28 days. If a sample contained 510 grams, how much chromium would remain after 56 days?
How much would remain after 1 year?
11.
The half-life of iodine-125 is 60 days. What fraction of iiodine-125 would be left after 350 days?
12. Titanium-51 decays by P " emission with a half-life of 6 minutes. What fraction of titanium would remain after 1 h?
13. A medical institution requests 1 gram of bismuth-214, which has a half-life of 20 min. How many grams of bismuth-214 must be
prepared and shipped, if the shipping time is exactly 2 h?
14. What fraction of radioactive strontium-90, formed in the last atmospheric nuclear-bomb test in 1963, will be present in the
environment in the year 2050? The half-life of strontium-90 is 29 years?
15. The half-life of phosphorus-30 is 2.5 min. What fraction of phosphorus-30 would remain after 10 min?
16. Chromium-48 decays by P^emission. After 6 half-lives, what fraction of the original nuclei would remain?
Name
WS Half-life 2
The Half-Life of Radon-226 is approximately 4 days. On the grid below, plot the amount of Radon-226 left
after each 4 day time period when you start with a 48g sample of Radon-226
1
-4
i
"i
\
i
\
j
1
i
1
i
••\
!
1
:
. j
.. . ;
i
\
•4
..1
4
j
i
1
i
1
!
1
;
1
i
i
1
1
1
1
j
1
!
1
r
:
1 .
1
\
;
.
:
:
Questions
1.
2.
3.
4.
5.
How many grams of radon would be present after
How many grams of radon would be present after
How many grams of radon would be present after
I f 8 g of radon are left, what is the time elapsed?
How many grams of radon would be present after
4 days?
12 days?
24 days?
6 days?
.
1
:
i
i
;
i
i
1
WS Decay Series of U-238
Name
1.
Complete the table using the decay series of U-238
238
3
CO
^0?
81
92
atomic number
2. Complete the reactions and mark the graph above with the nuclide that is formed.
238
U
92
238
u
92
234
Th
90
a
234
6
Pa
234
u
92
6
a
218
Po
84
a
a
222
Rn
86
a
226
Ra
88
230
th
90
a
214
82Pb
214 B i
83
214
Po
84
6
a
210
Pb
82
6
stable ^^^Pb
82
a
210
Po
84
83
Table N
Table K
Common Acids
Selected Radioisotopes
Name
Formula
Nuclide
HCl(aq)
hydrochloric acid
HN02(aq)
nitrous acid
HN03(aq)
nitric acid
H2S03(aq)
sulfurous acid
HgSO^lati)
sulfuric acid
H3P04(aq)
phosphoric acid
H2C03(aq)
or
C02(aq)
carbonic acid
Half-Life
2.695 d
14c
5715 y
-Ca
182 ms
5.271 y
30.2 y
13'CS
ethanoic acid
22UF,
27.4 s
1.23 s
Table L
10.73
NaOH(aq)
sodium hydroxide
KOH(aq)
potassium hydroxide
Ca(OH)2(aq)
calcium hydroxide
NH3(aq)
aqueous ammonia
Common Acid-Base Indicators
Indicator
Color
Change
methyl orange
3.1-4.4
red to yellow
bromthymol blue
6.0-7.6
yellow to blue
phenolphthalein
8-9
colorless to pink
litmus
4.5-8.3
red to blue
bromcresol green
3.8-5.4
vellow to blue
thymol blue
8.0-9.6
yellow to blue
Source: The Merck Index, 14'^ ed., 2006, Merck Publishing Group
Reference Tables for Physical Setting/Chemistry - 2011 Edition
gold-198
carbon-14
r
p-
cobalt-60
cesium-137
iron-53
a
francium-220
r
r
hydrogen-3
iodine-131
potassium-37
potassium-42
r
kiypton-85
(3-
nitrogen-16
l9Ne
17.22 s
(3^
neon-19
32p
14.28 d
|3-
phosphorus-32
10^ y
a
plutonium-239
1599 y
a
radium-226
3.823 d
a
radon-222
239p^
2.410
X
90s,
2.13
Table M
Approximate
pH Range
for Color
Change
7.13 s
16^1
Name
V
Nuclide
Name
calcium-37
12.36 h
42K
Formula
V
8.021 d
1311
(acetic acid)
Common Bases
r
8.51 min
12.31
CH3COOH(aq)
or
HC2H302(aq)
Decay
Mode
X
29.1 y
P-
strontium-90
lO^y
(3-
technetium-99
10^0 y
a
thorium-232
X
10\
a
uranium-233
7.04
X
10''^ y
a
uranium-235
4.47
X
lO'^ y
a
uranium-238
232Th
1.40
233u
1.592
235u
2 3 S u
X
Source: CRC Handbook of Chemistry and Physics,
CRC Press
91^* ed., 2010-2011,