1. On a sheet of loose leaf, write down the
SPARK
On a sheet of loose leaf, write down the
following:
What fraction of the original sample is remaining after one HALF life?
What fraction of the original sample is
remaining after TWO half lives?
What is the half life of Carbon-14 (HINT: use
your reference table N)
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP

2. SPARK Half Lives Passed Fraction Remaining 1 1/2 2 1/4 3 1/8 4 1/16 5
Regents Chemistry Unit: 4
SPARK
Can we make a chart to represent half life?
Half Lives Passed
Fraction Remaining 1
1/2 2
1/4 3
1/8 4
1/16 5
1/32
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP

3. LET’S MAKE THIS VERY SIMPLE
What fraction of a sample of gold-198 remains
radioactive after 2.69 days? a)
c) ¾ b)
d) 7/8
Now we could use some crazy math equations to solve this problem… instead let’s use the chart we made at the beginning of class and reference Table N
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP

4. LET’S PRACTICE TOGETHER
1. How much of a 100-mg sample of nitrogen-16 will remain after
28.8 seconds of decay?
Step 1: write down what you know… Started with 100 mg of N-16
Total time elapsed = 28.8 sec
Step 2: write down what you WANT to know… How much is left?
Step 3: find more information…
What is the half life of nitrogen 16?
Step 4: use the chart
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP

5. LET’S PRACTICE TOGETHER
1. After 62.0 hours, 1.0 gram remains unchanged from a sample of 42K. What is the total number of half life periods? How much 42K was in the original sample?
Step 1: write down what you know…
Step 2: write down what you WANT to know… Step 3: find more information…
Step 4: use the chart
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP

6. LET’S PRACTICE TOGETHER
1. How many half-lives are required for radioisotope to decay to 1/32 of its initial value?
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP

7. LET’S PRACTICE TOGETHER
Manganese-56 is a beta emitter with a half-life of
2.6 h. What is the mass of manganese-56 in a 1.0- mg sample of the isotope at the end of 10.4 h?
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP

8. YOUR TURN: YOU MAY TALK TO YOUR NEIGHBOR
How many half-life periods have passed if 80 grams of C-14 has decayed to 5 grams?
Use Table N to determine the half-life of C-14.
Determine the amount of time that has elapsed as C-14 decays from 80 g to 5 g. 1. 2. 3.
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP

9. PUSH IT Part 1: Identify the pattern in the following nuclear
Regents Chemistry Unit: 4
PUSH IT
Part 1: Identify the pattern in the following nuclear
equation.
1H + 4Be  3Li + 2He 1.
Part 2: Use the pattern to write the missing number into the different nuclear equation written below. 27
13Al + 2He  15P +0n
4 30
Part 3: In a few short sentences, describe how you came up with your answer to part 2.
AGENDA
1) SPARK
2) SHARE OUT
3) LESSON
4) CLASS WORK
5) WRAP UP