Name:__________________
Date:________________
Class: 12 _________
Chemistry worksheet –chapter 25
I. Types of Radioactive Decay
A. Alpha Emission – an alpha particle (α) is 2 protons and 2 neutrons (or a helium atom)
bound together and is emitted from the nucleus during some kinds of radioactive decay.
210
206
4
Po
→
Pb +
He
84
82
2
Clothes or paper will shield you from alpha particles.
B. Beta Emission – a beta particle (β) is an electron emitted from the nucleus when a neutron
is converted to a proton.
1
1
0
n
→
p
+
e
0
1
-1
14
0
C
→
____
+
e
6
-1
Metal foil will shield you from beta particles.
C. Gamma Emission – gamma rays (γ) are high-energy electromagnetic waves emitted
from a nucleus as it changes from an excited state to a ground energy state. Very similar to
light, but is much more dangerous. Gamma emission usually occurs immediately following
other types of decay.
Lead or concrete will protect you from gamma rays.
D. Positron Emission – a positron is a particle that is emitted from the nucleus when a
proton is converted into a neutron.
1
1
0
p
→
n
+
β
1
0
1
38
0
K
19
→
+
_____
CHEMISTRY WORKSHEET G 12/ (2021-2022)
β
1
1
II.
1.
Complete the following nuclear equations:
218
4
Po
→
He
+
84
2
_____________
2.
253
Es +
99
3.
142
Pm +
61
4.
206
Pb
82
5.
4
He
256
Md +
101
_________________
→
2
142
→
_____________
202
→
Cm
+
80
________________
234
0
Th
→
90
6.
40
Ca
20
III.
Nd
60
→
+
_____________
40
K
19
β
-1
+
________________
Problems:
1 . Write the nuclear equations for the following radioactive decay series. Use the periodic
table.
a. Platinum-196 is bombarded by a deuteron (H-2), producing platinum-197 and a proton.
___________________________________________________________________________
b. Nitrogen-14 is bombarded by a neutron, producing carbon-14 and a proton.
CHEMISTRY WORKSHEET G 12/ (2021-2022)
2
___________________________________________________________________________
c. Po-215 emits an alpha and a gamma
____________________________________________________
d. The product from above emits a beta
___________________________________________
3. If we start with 16 grams of a radioactive substance, how much will remain after three
half-lives?
4. The half-life of polonium-210 is 138.4 days. How many mg of polonium-210 remain after
415.2 days if you start with 2mg of the isotope?
5. The half-life of radon-222 is 3.824 days. After what time will ¼ of a given amount of
radon-222 remain?
6. After 36 days, 600 g of nitrogen -27 has decayed to 75 g. What is the half-life of
nitrogen-27?
7. With a half life of 28.8 years, how long will it take 1000 mg of strontium-90 to decay to
125mg?
CHEMISTRY WORKSHEET G 12/ (2021-2022)
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