1. “Problems are not stop signs, they are guidelines.”
Do Now
Before the bell rings
After the bell
Pick up today’s handouts
Get your interactive notebook
In your seat
Place your Half-Life homework on your desk with your name on it
Respond to the following:
“Problems are not stop signs, they are guidelines.”
-Robert Schuller
Still needs Do Now

2. Nuclear chemistry: Half-Life
Objective:
Describe the decay of isotopes through half-life

3. Agenda Standard  Do Now (5 min) Upcoming: Unit 2 Test Warm Up (5 min)
Notes: Half - Life(15 min)
Activity: Half-Life of a penny (20 min)
Independent Practice: (20 min)
Exit Slip (5 min)
Closeout (2 min)

4. Guiding Question
Why can’t you just clean up after a nuclear disaster?

5. Warm –Up: How? What? C – Level 1-2, amongst group H – Raise hand
What does the nucleus of an atom of K-42 contain? What is its charge?
How do the energy and the most probable location of an electron in the third shell of an atom compare to the energy and the most probable location of an electron in the first shell of the same atom?
In the third shell, an electron has more energy and is closer to the nucleus.
In the third shell, an electron has less energy and is closer to the nucleus.
In the third shell, an electron has less energy and is farther from the nucleus.
In the third shell, an electron has more energy and is farther from the nucleus.
C – Level 1-2, amongst group
H – Raise hand
A – Discuss prompt
M – None
P –Recording responses on left page, discussing with group

6. Isotope What is an isotope?
Isotope: any forms of an element that have the same number of protons, but a different number of neutrons.
In other words, it will be the same element, with a different atomic mass
Isotope

7. Isotope examples

8. Half - Life Half-Life Decay of a Radioactive Isotope Half-Life
Isotope remaining
100% 1
50% 2
25% 3
12.50% 4
6.25% 5
3.12%
Half - Life
Definition: The Amount of time it takes for one-half of a sample of atoms to decay.

9. March Madness Bracket
Looks like This…

10. How much will remain
Barium-122 has a half-life of 2 minutes. If you receive 80 g of Barium-122, how much will be remaining after 10 minutes?
Set up a 3 column table
Label the columns: half-life, time, amount
Fill in the information you are given (starting with time 0 and half- life 0, for original amount only)
Work forwards or backwards to reach the answer
Half-Life
Time
Amount
H-L Time Amount
0 0 80
2 40
4 20
6 10
8 5
10 2.5

11. How much of a 100. 0 g sample of 198Au is left after 8
How much of a g sample of 198Au is left after 8.1days, if its half-life is 2.70 days?
You Do
Set up a 3 column table
Label the columns: half-life, time, amount
Fill in the information you are given (starting with time 0 and half- life 0, for original amount only)
Work forwards or backwards to reach the answer
H-L Time Amount g

12. Mini – Lab: Half-Life How? Instructions are in your packet
What?
C – Level 1-2, on-task discussion
H – Raise hand
A – Answering questions as a small group at lab
M – None
P – Recoding answers on worksheet, head up, reading and thinking through all questions, discussing with group
Instructions are in your packet
Using 50 coins, not 100
Using Tupperware instead of Ziploc bags

13. Activity: Independent Practice
How?
What?
C – None
H – Raise hand
A – Answering questions to determine # of subatomic particles
M – None
P – Recoding answers on worksheet, head up, reading and thinking through all questions.
10 minutes silently  Discuss for 5 minutes in small groups  Verify & Review as class

14. Exit Slip How? What? (5 min)
C – No talking
H – Raise hand
A – Taking exit slip
M – In seat
P – Completing exit slip without notes and turning in
If you finish early, summarize what you learned at the bottom of your notes OR answer today’s guiding question

15. Forgetting to stretch is a bear.
Closing
What are 3 key takeaways from today and yesterday?