Chemistry: Matter and Change

Section 2: Radioactive Decay

Self Check Quizzes

1
If a thorium-230 atom undergoes alpha decay, what are the products of the reaction?
A)actinium and an alpha particle
B)actinium and a positron
C)radium and an alpha particle
D)radium and a positron
2
What happens during positron emission?
A)A proton is converted into a neutron and a positron.
B)A neutron is converted into a proton and a positron.
C)A proton is converted into a neutron and an electron.
D)An atomic explosion occurs.
3
The atomic number of an atom ________ when it undergoes positron emission.
A)decreases by 2
B)increases by 2
C)decreases by 1
D)increases by 1
4
If the half-life of C-14 is 5730 years, how much C-14 would be left from a 5000 year-old sample that started as 150 grams?

N = N0(1/2)t/T
A)54 grams
B)82 grams
C)68 grams
D)95 grams
5
After 7.0 half-lives, how much P-32 will be left from an original sample of 225 grams?

N = N0(1/2)n
A)1.8 grams
B)223 grams
C)227 grams
D)117 grams
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