Chemistry
Mr. Samaniego
Name:
Period:
Unit 2 – Atomic Structure
Atomic Structure (Ch.4) and Electrons in Atoms (Ch.5)
Week of
Sept. 26th
Block 1
Block 2
1. Ch 4.1 – Define Atom
2. Ch 4.2 – Atom Structure
HW – Chapter 4 Homework
Week of
Sept. 26th
1. CHAPTER 4 QUIZ
2. Ch 5.1 – Atom Models
3. **Ch 5.2 – e- config. and
orbital diagrams
HW – Chapter 5 Homework
**HONORS ONLY
Block 3
1. Ch 4.3 – Composition
2. Calculating Atomic Mass
3. Candium Lab
HW –Candium Lab Questions
1. Flame Test Lab
2. Review Chapter 5
HW – Unit 2 Review
1. Chapter 4 Review Game
HW – Chapter 4 Review
End of 5 Week Progress
Unit 2 Exam
California State Standards Covered in Unit 2
Atomic and Molecular Structure - The periodic table displays the elements in increasing atomic number and shows
how periodicity of the physical and chemical properties of the elements relates to atomic structure. As a basis for
understanding this concept:
 Students know the nucleus of the atom is much smaller than the atom yet contains most of its mass.
 Students know the experimental basis for Thomson's discovery of the electron, Rutherford's nuclear
atom, Millikan's oil drop experiment, and Einstein's explanation of the photoelectric effect.
 Students know the experimental basis for the development of the quantum theory of atomic structure
and the historical importance of the Bohr model of the atom.
Once you complete an assignment, you will receive a stamp in the box below the assignment.
You must completely fill all of the boxes before you are allowed to take the Unit 2 Exam.
Chapter
4 HW
Candium
Lab
Chapter
4 Review
Chapter
5 HW
Flame
Test
Unit 2
Review
TOTAL
SCORE
30
Parent Signature: ___________________________
Obstacles are those frightful things you see
when you take your eyes off your goals.
- Henry Ford
Chapter 4 Homework
1. Describe Democritus’ philosophy (what did he suggest?).
2. List the four parts of Dalton’s Atomic Theory.
3. Would you expect two electrons to attract or repel one another?
4. Explain the discovery of the electron (who, when, how).
5. Why does it make sense that if an atom loses electrons, it is left with a positive charge?
6. Describe the location of the electrons in Thomson’s “plum pudding” model of the atom.
7. Who determined the charge and mass of the electron?
8. What is the mass of an electron?
9. Explain Rutherford’s gold foil experiment.
10. Rutherford said that “Atoms are mostly _________________________.”
11. What is a nucleus?
12. What were the two main conclusions to Rutherford’s experiment regarding an atom’s
mass and volume?
13. Complete the table:
Particle
proton
neutron
electron
Charge
Location in Atom
Symbol
14. What is the difference between mass number and atomic number?
15. Why is an atom electrically neutral?
16. What is an isotope?
17. In what two ways are isotopes different?
18. Using a periodic table, complete the chart below.
ATOM
SYMBOL
ATOMIC
NUMBER
MASS
NUMBER
HELIUM
He
2
4
BROMINE
# OF
PROTONS
80
# OF
ELECTRONS
35
ALUMINUM
13
URANIUM
BORON
5
238
92
11
5
PHOSPHORUS
Fe
56
CHLORINE
15
15
26
26
17
STRONTIUM
38
Al
# OF
NEUTRONS
88
14
16
18
38
27
13
19. Write the following atoms in shorthand notation.
Element
Atomic
Mass Number
Number
Neon
10
20
Oxygen
8
16
Silver
47
108
13
Shorthand Notation
20. What is the difference between atomic mass and mass number?
21. The isotope 10X has a mass of 10.012amu and a relative abundance of 19.91%. The isotope
11
X has a mass of 11.009amu and a relative abundance of 80.09%.
22. The element copper has naturally occurring isotopes with mass numbers of 63 and 65.
The relative abundance and atomic masses are 69.2% for mass = 62.93amu, and 30.8% for
mass = 64.93amu. Calculate the average atomic mass of copper.
23. Calculate the atomic mass of bromine. The two isotopes of bromine have atomic masses
and relative abundance of 78.92amu (50.69%) and 80.92amu (49.31%).
24. What is the periodic table?
25. Differentiate between a period and a group.
The Atomic Mass of Candium Lab (page 120)
Purpose: to analyze the isotope “candium” and calculate its atomic mass
Materials: a sample of candium, electronic balance
Procedures:
1. Obtain a sample of candium
2. Separate the sample into three piles depending upon the type of candium
3. Measure the total mass of each isotope
4. Count the number of isotopes in each sample
5. Calculate the average mass, relative abundance, percent abundance, and relative mass of
each isotope of candium
Data Table: show your calculations in each box below
A
B
Total Mass
(weigh each sample
separately)
Number
(count each sample
separately)
Average Mass
(divide the total
mass by the number)
C
Total
Relative Abundance
(divide the number
of each sample by
the total number)
Percent Abundance
(multiply the relative
abundance by 100)
Relative Mass
(multiply the average
mass by the relative
abundance)
Conclusion:
1. What is an isotope?
2. What does each of the three types of M&M’s represent?
3. What does percent abundance really mean?
4. Describe the two steps in calculating how average atomic mass (from your notes).
Chapter 4 Review
Philosopher/Scientist
What Did They
Discover?
Describe the Experiment
Democritus
NONE
John Dalton
NONE
J. J. Thomson
Robert Millikan
Ernest Rutherford
Chapter 5 Homework
1. What did Rutherford’s atomic model not explain about atoms?
2. What did Bohr propose about the movement of electrons around an atom?
3. What is an energy level?
4. What is a quantum of energy?
5. What does the quantum mechanical atomic model determine?
6. What is an atomic orbital?
7. What is the shape of the s, p, and d orbital?
8. Identify the following elements.
ELEMENT
CLUES
2
2
6
2
3
2
2
6
2
6
1
2
2
6
2
6
2
10
2
2
6
2
2
2
6
2
6
2
7
1s 2s 2p 3s 3p
1s 2s 2p 3s 3p 4s
2
1s 2s 2p 3s 3p 4s 3d 4p
1s 2s 2p 3s
1s 2s 2p 3s 3p 4s 3d
9. Write a ground state electron configuration for each neutral atom. Use your filling order.
ELEMENT
ELECTRON CONFIGURATION
O
Na
S
K
Al
Cl
Xe
Ca
F
Br
N
Ar
I
Sr
Pb
Cu
Se
Si
Sr
Ag
Ti
Ce
Kr
10. Write a ground state electron configuration for these ions.
ELEMENT
ELECTRON CONFIGURATION FOR IONS
O2Fe2+
B3+
Ni2+
K+
Co3+
Fluorine1Selenium3-
11. Choose 2 possible elements or ions for the following electron configurations.
POSSIBLE ELEMENTS
ELECTRON CONFIGURATION
1s2
1s2
1s2
1s2
1s2
2s2
2s2
2s2
2s2
2s2
2p6
2p6
2p6
2p6
2p6
3s1
3s2
3s2
3s2
3s2
3p6 4s2
3p6 4s2
3p6 4s2
3p6 4s2
3d8
3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p4
3d10 4p3
3d10 4p6 5s2 4d7
12. State the Aufbau Principle.
13. State the Pauli Exclusion Principle.
14. State Hund’s Rule.
15. Draw an orbital diagram for each of the following elements.
ELEMENT
1
Al
2
Be
3
C
4
O
5
Na
6
S
7
Ne
ORBITAL DIAGRAM
# OF
PAIRED E-
# OF
UNPAIRED E-
Flame Test
When ions or vapors of metals are heated in a flame, some of their electrons gain energy. These
electrons move from their ground state to a high energy level. As they return to their previous
state, these electrons lose energy in the form of light. Different metal ions produce different
colors of light. Fireworks are a practical application of this phenomenon.
Procedure
1. Swirl the popsicle stick into the chemical making sure that a few grains of the salt stick
to the splint.
2. Wave the popsicle stick in and out of the flame and record the color of the flame in your
data table.
3. Draw a colored picture of your flame in the data table below.
4. Once you have used both sides of the popsicle stick, place it in the waste container.
***USE 1 WOODEN SPLINT FOR 2 COMPOUNDS***
Data Table
Name of Compound
1. NaCl
2. LiCl
3. CaCl2
4. CuCl2
5. KCl
6. SrCl2
7. MgCl2
8.
BaCl2
UNKNOWN A
UNKNOWN B
Describe the Color of the
Flame
COLORED Picture
Conclusion Questions
(1.) What color was the flame of Unknown A? From looking at the results of your experiment,
what metal ions is the unknown compound composed of?
(2.) What color was the flame of Unknown B? From looking at the results of your experiment,
what metal ions is the unknown compound composed of?
(3.) E.T. comes to visit you and brings along some alien crystals. How could you identify the
elements in these crystals? Be specific.
(4.) When a pan of milk boils over onto the stove, the flame turns red-orange. Explain why.
(5.) A firework contains Copper Chloride and Strontium Sulfate. What colors will the
explosives produce?
(6.) What colors would you expect a mixture of Strontium Sulfate and Strontium Nitrate to
produce? Why?
(7.) How do you think the study of light emission can help determine the composition of
stars?
(8.) Where could some possible errors or causes of inaccuracies come from in this
experiment? Be specific.
Unit 2 Review
1. What are the principles of Dalton’s atomic theory?
2. How did each of the following scientists contribute to the model of the atom?
a. Dalton
b. Rutherford
c. Thomson
d. Bohr
3. All neutral atoms have the same number of what?
4. What is the nucleus of the atom? What particles make up the nucleus?
5. What is an isotope? Give an example of one.
6. What information is necessary to calculate the atomic mass of an element?
7. What does the number 84 in “Krypton-84” represent?
8. How many neutrons are in Nitrogen-14?
9. What is the atomic number for an element with 41 neutrons and a mass number of 80?
10. How many protons are present in an atom of Be-9?
11. How many electrons are in a neutral atom of Calcium?
12. How many neutrons are in
210
Pb?
13. What is an atomic mass unit equal to?
14. Consider an element Z that has two naturally occurring isotopes with the following
percent abundances: the isotope with a mass number of 19.0 is 55.0% abundant; the
isotope with a mass number of 21.0 is 45.0% abundant. What is the average atomic mass
for element Z?
15. What does the quantum mechanical model of the atom describe?
16. True or False: “The mass of a neutron nearly equals the mass of a proton.”
17. True or False: “The energy of an electron increases as it moves closer to the nucleus.”
18. True or false: “Emission of light from an atom occurs when an electron drops from a
higher to lower energy level.”
19. What is the shape of each of the following orbitals?
a. S orbital
b. P orbital
c. D orbital
d. F orbital
20. What is the maximum number of p orbitals in an atom?
21. How does a pair of electrons spin in an orbital?
22. Draw and write out the entire filling order of electron configurations.
23. Write out the electron configuration for the following neutral atoms.
a. Potassium
b. Beryllium
c. Chlorine
d. Boron
e. Neon
f. Sodium+1
g. Oxygen-2
24. Describe the following rules for drawing orbital diagrams:
a. Hund’s Rule
b. Aufbau Principle
c. Pauli Exclusion Principle
25. Draw orbital diagrams for the following elements:
a. Sodium
b. Magnesium
c. Phosphorus