The Electron Configuration of
Atoms C-SE-TE
Richard Parsons, (RichardP)
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Printed: November 17, 2014
AUTHOR
Richard Parsons, (RichardP)
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Chapter 1. The Electron Configuration of Atoms C-SE-TE
C HAPTER
1
The Electron Configuration
of Atoms C-SE-TE
C HAPTER O UTLINE
1.1
Electron Arrangement
1.2
Valence Electrons
1.3
Multimedia Resources for Chapter 7
1.4
Laboratory Activities for Chapter 7
1.5
Worksheets for Chapter 7
1.6
Extra Readings for Chapter 7
1.7
Assessment for Chapter 7
Lessons and Number of Activities for Lessons
TABLE 1.1: Lessons and Activities for Lessons
Lesson
No. of Labs
No. of Demos
No. of Worksheets
1.
Electron Arrangement
2. Valence Electrons
0
0
2
No. of Extra Readings
0
1
0
2
1
1
1.1. Electron Arrangement
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1.1 Electron Arrangement
Student Behavioral Objectives
The student will:
•
•
•
•
•
draw the orbital representation for selected atoms.
write the electron configuration code for selected atoms.
identify the principal, angular momentum, magnetic, and spin quantum numbers.
identify the four quantum numbers for indicated electrons.
identify the energy level, sub-energy level, orbital, and spin for an electron given the four quantum numbers
for the electron
Timing, Standards, Activities
TABLE 1.2: Timing and California Standards
Lesson
Electron Arrangement
Number of 60 min periods
3.0
CA Standards
1g
Activities for Lesson 1
Laboratory Activities
1. None
Demonstrations
1. None
Worksheets
1. Orbital Configuration Worksheet
2. Quantum Numbers Worksheet
Extra Readings
1. None
Answers for Electron Arrangement (L1) Review Questions
• Sample answers to these questions are available upon request. Please send an email to teachers-requests@ck12.org
to request sample answers.
2
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Chapter 1. The Electron Configuration of Atoms C-SE-TE
1.2 Valence Electrons
Student Behavioral Objectives
The student will:
• define valence electrons.
• indicate the number of valence electrons for selected atoms.
• draw Lewis dot diagrams for selected atoms.
Timing, Standards, Activities
TABLE 1.3: Timing and California Standards
Lesson
Valence Electrons
Number of 60 min periods
1.0
CA Standards
2e
Activities for Lesson 2
Laboratory Activities
1. Diamagnetic Levitation
Demonstrations
1. None
Worksheets
1. Electron Configuration Worksheet
2. Electron Dot Formulas Worksheet
Extra Readings
1. Orbital Filling Order Exceptions
Answers for Valence Electrons (L2) Review Questions
• Sample answers to these questions are available upon request. Please send an email to teachers-requests@ck12.org
to request sample answers.
3
1.3. Multimedia Resources for Chapter 7
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1.3 Multimedia Resources for Chapter 7
This website has a lesson on atomic structure.
• http://www.chemtutor.com/struct.htm
This website gives the apartment analogy of electron configuration.
• http://kaffee.netfirms.com/Science/activities/Chem/Activity.Electron.Configuration.html
This video discusses the physical interpretation of quantum numbers.
• http://www.youtube.com/watch?v=e9N2h8c6dE4
This video explains the four quantum numbers which give the "address" for an electron in an atom.
• http://www.youtube.com/watch?v=63u7A2NIiyU
This website has lessons, worksheets, and quizzes on various high school chemistry topics. Lesson 3-6 is on electron
configuration.
• http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson36.htm
These two websites examine the discovery of the spin quantum number.
• http://www.lorentz.leidenuniv.nl/history/spin/goudsmit.html
• http://www.ethbib.ethz.ch/exhibit/pauli/elektronenspin_e.html
This video provides an introduction to the electron configuration of atoms.
• http://www.youtube.com/watch?v=fv-YeI4hcQ4
This website has lessons, worksheets, and quizzes on various high school chemistry topics. Lesson 3-8 is on Lewis
dot diagrams.
• http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson38.htm
4
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Chapter 1. The Electron Configuration of Atoms C-SE-TE
1.4 Laboratory Activities for Chapter 7
The Electron Spin Quantum Number Lab –Diamagnetic Levitation
In this chapter, we discussed the differences between diamagnetic and paramagnetic material. In this lab, we suggest
demonstrating how a diamagnetic material is slightly repelled by a magnetic field.
Materials:
A thin sheet of pyrolytic graphite
A set of magnets
A complete diamagnetic levitation kit can be bought from certain school supply websites. A reasonably priced kit can
be found at http://www.teachersource.com/ElectricityAndMagnetism/ElectricityAndMagnetism/DiamagneticLevitati
onKit.aspx
Method:
Place the graphite above the magnets and watch it float!
5
1.5. Worksheets for Chapter 7
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1.5 Worksheets for Chapter 7
Copy and distribute the lesson worksheets. Ask students to complete the worksheets alone or in pairs as a review of
lesson content.
Orbital Configuration Worksheet
CK-12 Foundation Chemistry
Name_______________________ Date__________
TABLE 1.4: Draw the Orbital Configuration for these Atoms
Symbol
Mg
P
Ge
Kr
6
Orbital Diagram
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Chapter 1. The Electron Configuration of Atoms C-SE-TE
TABLE 1.4: (continued)
Symbol
O
Orbital Diagram
F
Pb
TABLE 1.5: Write the Electron Configuration Code for these Atoms
Atom
V
Mg
P
Ge
Kr
O
F
Pb
Electron Configuration Code
1s2 2s2 2p6 3s2 3p6 4s2 3d 3
Quantum Numbers Worksheet
CK-12 Foundation Chemistry
Name______________________ Date_________
1.
2.
3.
4.
5.
6.
Which quantum number indicates the electron’s energy level?
Which quantum number indicates the electron’s sub-energy level?
Which quantum number indicates the electron’s orbital within the sub-energy level?
Which quantum number indicates the electron’s spin?
What is the lowest energy level that has a d sub-level?
What is the total number of electrons that can exist in the 3rd energy level?
7
1.5. Worksheets for Chapter 7
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Which sub-energy level is indicated by ` = 1?
which sub-energy level is indicated by ` = 2?
What is the maximum number of electrons that can be held in an f sub-energy level?
What does it mean for an electron to be “excited”?
What are the n and ` quantum numbers for the last electron in bromine?
What are the n and ` quantum numbers for the last electron in iron?
What are the n and ` quantum numbers for the electron in hydrogen?
The three electrons in the 2p sub-energy level of nitrogen have the n and ` quantum numbers. What are the
m` quantum numbers for each of these three electrons?
What is the basic tenet of the quantum theory?
Why are the quantum numbers n = 2, ` = 2, m` = 2, s = 12 , not an acceptable set of quantum numbers for an
electron?
Sketch a picture of the 2s sub-energy level showing any nodes present.
Give the full set of quantum numbers for each of the electrons in a helium atom.
What maximum number of electrons in an atom can have the quantum numbers n = 2, ` = 1?
What maximum number of electrons in an atom can have the quantum numbers n = 3, ` = 3?
Electron Configuration Worksheet
CK-12 Foundation Chemistry
Name______________________ Date_________
1. Fill in the orbital electron representation for phosphorus.
2. Fill in the electron orbital configuration for cobalt.
8
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Chapter 1. The Electron Configuration of Atoms C-SE-TE
3. Fill in the electron orbital configuration for bromine.
4. Draw the orbital representation for the electron configuration of calcium.
5. Write the electron configuration code for phosphorus.
6. How many valence electrons does phosphorus have?
7. Write the electron configuration code for cobalt.
9
1.5. Worksheets for Chapter 7
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8. How many valence electrons does cobalt have?
9. Write the electron configuration code for bromine.
10. How many valence electrons does bromine have?
11. Write the electron configuration code for calcium.
12. How many valence electrons does calcium have?
13. How many valence electrons does tellurium have?
14. What will be the outer energy level electron configuration for element #118?
15. Draw the orbital representation of the electron configuration for silicon.
16. How many valence electrons does silicon have?
Electron Dot Formulas Worksheet
CK-12 Foundation Chemistry
Name______________________ Date_________
1. Draw the electron-dot formula for phosphorus.
2. Draw the electron-dot formula for bromine.
3. Draw the electron-dot formula for cobalt.
4. Draw the electron-dot formula for calcium.
5. Draw the electron-dot formula for silicon.
6. Draw the electron-dot formula for element #118.
Answers to Worksheets
• The worksheet answer keys are available upon request. Please send an email to teachers-requests@ck12.org
to request the worksheet answer keys.
10
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Chapter 1. The Electron Configuration of Atoms C-SE-TE
1.6 Extra Readings for Chapter 7
Orbital Filling Order Exceptions
In assembling the electron configurations for many-electron atoms, one tool that students find valuable is the diagonal
rule. This rule provides a guideline that is readily remembered and easily followed to produce accurate electron
configurations for even complicated d− and f − block atoms. One confusing consequence of the diagonal rule is the
order of filling the 4s and 3d subshells.
When these orbitals are filled, they are very close in energy. Though as the electrons begin to occupy the empty
orbitals, the 4s level is slightly lower in energy than the 3d, thus it is filled first. On the other hand, when both are
occupied with electrons, the 4d orbital becomes higher in energy. Thus, in the case that both of these filled levels
are composed of valence electrons, the 4s level loses its valence electrons before the 3d level.
The preferential filling of the 4s orbital can also be explained by means of the electron penetration effect. Due to the
spherical shape of the s orbital probability density distribution, the likelihood that an electron is found closer to the
nucleus is greater than the multi-lobed 3d orbitals.
The similarity in the energy levels of the 4s and 3d orbitals also leads to another interesting consequence. In
the electron configuration of the neutral Chromium atom with 24 electrons, the diagonal rule suggests an electron
configuration of 1s2 2s2 2p6 3s2 3p6 4s2 3d 4 . The actual electron configuration is 1s2 2s2 2p6 3s2 3p6 4s1 3d 5 , where due
to the similarity in energy between the 4s and 3d orbitals, one electron transfers from the 4s to the 3d orbital.
The net effect of this exchange yields half-filled 4s and 3d orbitals, and therefore can be justified in terms of
generating additional stability. This is also the case for neutral copper atoms, with 29 electrons and a putative electron
configuration of 1s2 2s2 2p6 3s2 3p6 4s2 3d 9 . Again as in the example of chromium, an electron transfer occurs, shifting
one electron from the 4s orbital to the 3d orbital. For copper, the 4s orbital is now half-filled but added stability is
attained by completing the 3d subshell.
The stability afforded to half-filled orbitals is also noted among the f −block elements. For example, the electron configuration for Europium (atomic number 63) is 1s2 2s2 2p6 3s2 3p6 4s2 3d 10 4p6 5s2 4d 10 5p6 6s2 4 f 7 whereas the
next atom, Gadolinium, with atomic number 64, has the additional electron added to the 5d orbital in order to
maintain the half-filled stability of the 4 f 7 configuration. The electron configuration for Gadolinium is therefore
1s2 2s2 2p6 3s2 3p6 4s2 3d 10 4p6 5s2 4d 10 5p6 6s2 4 f 7 5d 1 .
The unusual stability of half-filled orbitals can be explained in terms of the disruption afforded by the addition of
another electron to this configuration. After the orbital is half-filled, the next additional electron must pair up with
another electron, increasing the spin-spin interaction energy and destabilizing the configuration.
11
1.7. Assessment for Chapter 7
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1.7 Assessment for Chapter 7
• The chapter quiz and answer key are available upon request. Please send an email to teachers-requests@ck12.org
to request the material.
12