1. On the front page of the Packet!
Launch
Get Out Your Unit 2 Packet, calculator, and a pen/pencil
Grade yourself on ALT 2
Open to the Unit 2 Study Guide
Write One thing you still don’t get.
Two things you totally “get.”
Be prepared to ask about what you don’t get as we go through the guide
11/12 (Th)
On the front page of the Packet!

2. Unit 2: Atoms and Radioactivity
Learning Target:
I can use models to describe how changes in the internal structure of the atom (protons, neutrons, and electrons) & determine the properties and identity of the atom.

3. Teacher Directed Review of Guide
Purpose: Answer student questions
PLEASE:
No side-conversations
Raise your hand to join in
Correct your answers as we go
There will not be time to copy these answers into a blank study guide.

4. ATOMS Essential Question
How are the smallest bits of matter described?
ATOMS

5. Evidence Supporting Model
Scientist
Evidence Supporting Model
John Dalton
He mixed elements in chemical reactions. He saw that they always combined in whole number ratios:
Like 1:2 or 3:2
 JJ Thomson
He zapped atoms with electricity and saw that negatively charge particles were ejected.
Ernest Rutherford 
He shot alpha particles at gold foil and saw that a few bounced back instead of going through. He hypothesized there must be a small, dense area inside the atom.
 Neils Bohr
He devised a model with electrons in orbits that explained the different flame colors of the elements.

6. The subatomic particles of atoms
Particle Name
Symbol
Charge
Location
Mass (amu)
Proton p+ +1
Nucleus
1 amu
Electron e- -1
Around the nucleus
Basically 0
Neutron n0

7. When are atoms electrically neutral?
Protons
+ 1 charge
Electrons
-1 charge
When protons = electrons

8. Atoms by the Numbers 9 F 19.00 10 19 26 Fe 55.85 30 56 3 Li 9.012 4 7
Atomic #
Symbol of element
Avg. atomic mass (amu)
Number of protons
Number of neutrons
Atomic** Mass
(amu)
Number of electrons 9 F
19.00 10 19 26 Fe
55.85 30 56 3 Li
9.012 4 7 K
39.10
41-22=19 22 41
** Do NOT use the periodic table to calculate this! #p + #n0

9. ISOTOPES Essential Question
How can atoms of the same element be different?
ISOTOPES

10. Isotopes Beryllium-5 4 1 5 Potassium-40 19 21 40 Potassium-39 20 39
Isotope Name
Atomic number
# of protons
# of neutrons
Atomic Mass (amu)
# of electrons
Isotope Symbol
Beryllium-5 4 1 5
Potassium-40 19 21 40
Potassium-39 20 39
Lithium-6 3 6
Lithium-7 7

11. Compare/Contrast Isotopes of an element
Li-6
Li-7
n0 = 4
Mass is 7 amu
Symbol has a 7 in upper left
n0 = 3
Mass is 6 amu
Symbol has a 6 in upper left
atomic # is 3
Symbol is Li
p+ is 3
e- is 3

12. Simple Atomic Model Be

13. The average atomic mass of copper is 63. 55 amu
The average atomic mass of copper is amu. This tells me that most of the atoms must be copper-63 since 63 amu is closer to the average than 65 amu for copper-65.
Cu-63
Cu-65
63.55 amu

14. Calculate average atomic mass
Isotope
Mass (amu)
Abundance (%) 28 92 29 5 30 3
Si-28 X =
= amu =
Si-29 X
= 1.45 amu =
Si-30 X
= 0.9 amu
28.11 amu
1. Convert each abundance to a decimal
2. Multiply each mass by its abundance
3. Add these up to get the average atomic mass

15. RADIOACTIVE DECAY Essential Question
How can we change an element’s identity?
RADIOACTIVE
DECAY

16. Best shielding (what blocks it)
Types of Radiation
Radiation
Symbol
Charge
Mass (amu)
Best shielding (what blocks it)
Alpha +2 4
Paper
Beta -1
Aluminum foil
Gamma γ
Lead or thick concrete

17. Nuclear Equations

18. Chemistry Test Day
Selfie
Then
OFF AND AWAY
All Period

19. Assessment Testing Procedures Did you FINISH the test or quiz?
You may not leave the room for any reason once you start the Exam.
NO EXCEPTIONS.
Ground Rules
Keep eyes on own papers.
Work silently.
No cell phones, iPods, etc.
AHS Integrity policy is in effect.
Assessment
Did you FINISH the test or quiz?
Flip it over, take out a book, or other silent activity. remain seated