• List the two symbols that scientists use to
represent a(n)…
– Alpha particle?
– Beta particle?
α
β
Thorium-230 has a half life of 8000
years. How long will it take a 100 g
sample of Th-230 to decay to 25 g?
Find how many half-lives it takes to decay to 25 g.
100  50  25
2 half-lives.
2 x 8000 = 16,000 years
Would Phosphorus-32 be stable?
15 protons, 17 neutrons
YES!
• When a nucleus undergoes alpha decay, what
will happen to the mass? the atomic number?
Mass decreases by 4 amu,
Atomic number decreases by 2
• When a nucleus undergoes beta decay, what
happens to the mass? the atomic number?
Mass doesn’t change, Atomic
number increases by 1
1. Identify the type of decay
2. How do you know?
•
Carbon-14 becomes nitrogen-14
•
Rn (radon) decays to become Po (polonium) α
•
Lead (Pb) becomes Bismuth (Bi)
•
Polonium-214 becomes lead-210
β
β
α
Write the equation for the radioactive
decay of the following elements:
• Uranium-234 (U, alpha decay)
234
U
92
4
He
+
2
230
Th
90
• Bismuth-214 (Bi, beta decay)
214
Bi
83
0
e
+
-1
214
Po
84
An organism contained 200 grams of
Carbon-14 when it died. After 17,190
years, only 25 grams remain. How
long is Carbon-14’s half-life?
Find how many half-lives have passed.
200  100  50  25
3 half-lives
17,190/3 = 5,730 years
How many neutrons would a stable
isotope of Tin (Sn) have?
58-75
Name the 2 forces working in the
nucleus of an atom.
Attractive Force: Strong Nuclear Force
Repulsive Force: Electrostatic Force
What is the difference between fusion
and fission? Draw a picture showing
the difference.
Fusion: combining 2 nuclei, more
energy released than fission, stars
and hydrogen bomb
Fission: splitting a nuclei, energy is
released, nuclear powerplants
and atomic bombs
Write the products of the following
fusion reactions:
4
+
He
2
12
4
4
8
He
2
C
+
He
6
2
Be
+
Energy
4
16
8
O + Energy
Write a radioactive decay equation
that will produce/make magnesium-24
- Using alpha decay
- Using beta decay
28
Si
14
24
Na
11
4
He
+
2
0
e
+
-1
24
Mg
12
24
Mg
12
• Radium-222 (Ra, alpha decay)
222
Ra
88
4
He
+
2
218
Rn
86
• Iodine-131 (beta decay)
131
I
53
0
- +
e
-1
131
Xe
54
Write a radioactive decay equation
that will produce/make Silver-108:
- Using alpha decay
- Using beta decay
112
In
49
108
Pd
46
4
He
+
2
0
e
+
-1
108
Ag
47
108
Ag
47