Decay Chain Worksheet-Teacher Answer Key
Examine each decay chain and identify the element. Then indicate whether each transformation is
due to the emission of an alpha or beta particle by writing in the corresponding symbol. Sometimes
gamma rays are released but because the release of gamma rays does not affect atomic mass or
atomic number the exercise is focused on alpha and beta emissions.
60
27
Co It
—-A,	.
5.27 Years
Nickel-60
60
28
Ni
Radon-222
222
Rn
3.8 days
X
a
218
84
Po
a
Polonium-218
3 minutes

Lead-214
214
82
Pb
P
27 minutes
%
214
83
Bi
Bismuth-214
Key
Alpha particle: OC
Beta particle:
Gamma ray: y
Rn
In the example, Rn is the
atomic symbol for the element
Radon. The number 222
indicates the atomic mass of
the element (or isotope). The
number 86 represents the
element's atomic number.
-X
p
20 minutes
210
Po
a
Polonium-210

.0002 seconds
Lead-206
206
82
Pb
vvEPA
United States
Environmental Protection
Agency
EPA 402-B-19-024
RadTown Radioactive Atom Activity Set
https://www.EPA.gov/RadTown/Activitv-6-Radioactive-Decay-Chain

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