Teacher Notes
Name
Key
Class
Date
Nuclear Decay
Types of Radiation
1. Complete the table below to compare the properties of alpha, beta, positron, and gamma radiation.
Name
Alpha
Beta
Positron
Gamma

-
+

He
0
1
0
1
Greek letter
4
2
Symbol
e
N/A
2p+, 2n0
electron
anti-electron
EM wave
2+
1-
1+
0
paper, skin,
clothing
wood, glass
wood, glass
thick concrete or
lead
Composition
Charge
Stopped by
e
Nuclear Decay Reactions
In problems 2 – 5, fill in the missing particle for each nuclear decay reaction. Then, match each equation
to the appropriate type of nuclear decay.
C 147N  10 e
2.
14
6
D
3.
32
17
A
4.
218
84
C
5.
142
61
B
A. alpha emission
B. beta emission
Cl  e S
0
1
32
16
C. electron capture
D. positron emission
Po24He  214
82 Pb
Pm 10e142
60 Nd
In problems 6 and 7, write a balanced equation for each nuclear decay reaction.
6. Decay of radium-223 by alpha () emission.
7. Decay of iodine-126 by positron (+) emission.
223
88
Ra 24He  219
86 Rn
126
53
I 10 e 126
52Te
8. How are the atomic number and mass number of a nuclide affected by positron emission?
Atomic number decreases by one. Mass number stays the same.
9. How are the atomic number and mass number of a nuclide affected by the emission of gamma radiation?
Both atomic number and mass number stay the same since gamma radiation has no mass or
charge.
10. Which has a slightly greater mass in a nuclear reaction, the reactants or the products? Why?
The reactants have a slightly greater mass. In a nuclear reaction, a small amount of mass is
converted to energy according to the equation E = mc2. The difference in mass is referred
to as the mass defect.
Teacher Notes
Fission and Fusion
1. In a nuclear reaction, the atom’s nucleus changes; in a chemical reaction, the atom’s
change.
electrons
2. How is the mass defect calculated? Mass defect is the difference between the mass of the
reactants and the mass of the products in a nuclear reaction.
3. Differentiate between fusion and fission. Fusion is the joining of two nuclei and occurs naturally
in the stars. Fission is the splitting of one nucleus and is used in nuclear power plants.
4. Calculate the energy in joules released during the nuclear explosion at Hiroshima given a mass defect
of 1.0 gram. E = mc2 where m is the mass in kilograms and c is 3.00  108 m/s.
1.0 g
1 kg
1000 g
= 0.0010 kg
E = mc2 = (0.0010 kg)(3.00  108 m/s)2 = 9.0  1013 J
5. Balance each of the following nuclear reactions. Label each as decay, fusion or fission.
6.
a
a.
b.
c.
d.
C 
decay
a.
14
6
fusion
b.
2
fission
c.
236
92
decay
d.
13
8
fission
e.
235
92
14
7
N +
0
1
e
H + 2 H  4 He
U 
O
94
36
13
7
Kr +
N +
U + 01 n 
0
1
90
37
139
56
Ba + 3 01 n
e
Rb +
144
55
Cs + 2
1
0
n
(How many neutrons are emitted?)
Which of the following is an example of a fusion reaction?
the sun and stars
nuclear power plants
nuclear submarines
Hiroshima bomb