WorksheetsHalf life calculations
Total questions: 20
Worksheet time: 28mins
After 22,800 years, approximately what percentage of the original carbon-14 remains?
15%
12.5%
6.25%
3.125%
The % of the parent isotope remaining after 1 Half Life.
50%
25%
12.5%
6.25%
The % of the parent isotope remaining after 2 Half Lives.
50%
25%
12.5%
6.25%
The diagram shows 32 atoms
32 of the Red are the parent isotope
0 of the atoms are daughter isotopes
How many half-lives have occurred?
0
1
2
3
The diagram shows 32 atoms.
16 of the Red are parent isotopes
16 of the Green are daughter isotopes
How many half-lives have occurred?
0
1
2
3
What is the Half life of this isotope?
5 seconds
10 seconds
15 seconds
20 seconds
What is the Half Life of this isotope?
3 days
5 days
8 days
10 days
How many grams are left after 1 half life?
Why do some elements have half-lives?
they radioactively decay
half of their atom gets stolen
They are Twizzlers that break in half
Radioactive carbon-14 is often useful in determining the absolute age of geologic samples because radioactive isotopes
decay at a regular rate
become less stable during decay
remain unchanged over time
stabilize after four half-lives
Which diagram best represents the percentage of this radioactive isotope sample that will remain after 2 half-lives?
The Half Life of Californium 252 is 5 years.
TRUE
FALSE
The mass of a parent isotope is 100 g. How many grams of the parent isotope will remain after 2 half-lives?
25
50
12.5
0
A 50.0 g sample of a radioactive element has a half-life of 40 years. How much mass will be left after 80 years?
50
25
12.5
6.25
How long would it take for an element with a half-life of 100 years to reach 5 half-lives?
50
500
5000
5
