1. One Point Quiz One quiz per table, list everyone’s name
Agree on an answer
You have two minutes
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2. Laboratory Reports
Each lab report in Chemistry 115 is due the laboratory after you complete the analysis of your unknown.
Follow the format in the laboratory manual (M5-M6).
The report must be typed or word processed.
Deadline for Laboratory Report A
FRIDAY, January 11 (Week 5)
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3. Laboratory Reports
Okay to set up your own form following the general format shown in the laboratory manual. There is a template on-line in the class folder.
Only two (2) pages long.
Be sure to include your UNKNOWN # and sign the report.
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4. Laboratory Reports Probable other final deadlines
Report B: Monday Week 7
Report C: Monday Week 9
Report D: Monday Week 10
Unknown B: Three possible ions:
Ba2+, Cd2+, Mn2+
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5. Periodic Trends Edward A. Mottel Department of Chemistry
Rose-Hulman Institute of Technology

6. First Ionization Potential (IP)H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca
100
200
300
400
500
600 5 10 15 20
Atomic Number
Energy (kcal/mol)
Where on the periodic table are
the highest first IP values located?
Where on the periodic table are the
lowest first IP values located?
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7. First Ionization Potential (IP)
Ionization energy (IE)
highest
lowest
The trend is
not perfect
Many inconsistencies can be associated
with electronic configuration and
changes in orbital spherical symmetry
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8. kcal/mol H
313.4 He
567.0 Li
124.4 Be
215.0 B
191.3 C
259.7 N
335.2 O
314.1 F
401.8
Ionization Potential
Identify the trends
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9. kcal/mol
497.3
118.5
176.3
138.0
188.0
241.8
238.9
299.0 Ne Na Mg Al Si P S Cl Ar
363.4
Ionization Potential
Identify the trends
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10. Size Atomic Radii (Å) Why does the size decrease,Na
1.90 Mg
1.60 Al
1.43 Si
1.32 P
1.28 S
1.27
metallic radii
Why does the size decrease,
even though the number of electrons are increasing?
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11. Nucleus-Electron Charge Attraction+ e– +
F =
(e) (Ze) r2
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12. Orbital Set Size z y x 2px 2s The size of an atom or ion is defined
by the radius of the outermost
(valence) electrons.
2px 2s x y z
In going across a period,
the radial distance of the electrons
in the valence orbitals is about the same.
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13. Atom Size and Nuclear Charge
The number of protons (nuclear charge)
and electrons are both increasing Na 11 Mg 12 Al 13 Si 14 P 15 S 16
The increase in nuclear charge contracts the orbital set
slightly, resulting in a smaller atom.
(going from left to right)
The orbital set can hold the additional electrons
without having to get larger.
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14. Size Atomic Radii (Å) What opposing factors cause the size ofNa
1.90
1.86 Ar
1.92 Mg
1.60 Al
1.43 Si
1.32 P
1.28 S
1.27 Cl
1.40
metallic radii
van der Waals radii
What opposing factors cause the size of
phosphorous and sulfur to almost be the same?
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15. Electron-Electron Charge Repulsion
F =
(e) (Ze) r2 e– + P S
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16. Nonpolar Covalent Radii (Å)
Orbitals of larger
principle quantum
number (n) are
larger and further
from the nucleus.
Na 1.54 Li K
Rb 2.11
Cs 2.25
r =
4 p2 mZe2
n2 h2
This results in the
atom or ion size
increasing from
top to bottom.
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17. Atom and Ion Size Tends to increase right to left top to bottom
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18. Isoelectronic Species
Isoelectronic atoms and ions have the
same electronic configuration
1s2 2s2 2p6 3s2 3p6
Cl-
181 pm Ar
174 pm K+
133 pm
ionic and covalent radii
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19. Isoelectronic Series 1s2 2s2 2p6 3s2 3p6
0.5 1
1.5 2
2.5 14 16 18 20 22 24
Atomic Number
Radius (A)
Which atom or ion does
each point represent?
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20. Rank the oxygen(II) ion, oxygen atom and oxide ion in terms of size
Explain the relative sizes.
Nuclear
Number of
Ionic
charge
electrons
radii (Å)
O2+ 8 6
0.44 O 8 8
0.73
O2– 8 10
1.40
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21. Rank the hydride ion, helium atom and lithium ion in terms of size
Explain the relative sizes.
Nuclear
charge
Number of
electrons
Ionic
radii (Å) H– 1 2 He
Li+ 3
2.08
0.93
0.60
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22. +2 Ions of the First Transition Series
electrons
Nuclear
charge
Number
radii (A) Ti 2+ V Cr Mn Fe Co Ni Cu Zn 22 23 24 25 26 27 28 29 30 of 20 21
ionic
1.00
0.93
0.94
0.97
0.92
0.89
0.83
0.87
0.88
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23. +2 Ions of the First Transition Series
0.8
0.9 1 2 4 6 8 10
d electrons
Radius (A)
What is the overall trend?
Why isn’t the trend perfect?
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24. Inert Gas Configurations
Many atoms gain or lose electrons in attempting
to gain an inert gas configuration He Ne Ar Kr Xe Rn
Compare the electronic configurations of
O2–, F–, Ne, Na+, Mg2+, Al3+
isoelectronic
1s2 2s2 2p6
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25. Which of these ions is the smallest and which is the largest?
outer
shell
electrons
outer shell
electronic
configuration
isoelectronic
inert gas
S2– 8 3s 2 3p 6
argon
Cl– K+
Ca2+
Sc3+
Which of these ions is the smallest
and which is the largest?
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26. Inert Gas Electronic Configuration Rule
(ions with the electronic
configuration s2p6) 8
octet rule 18
eighteen
electron rule
(ions with the electron configuration s2d10p6)
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27. Eighteen Electron Rule (an extension of the inert gas configuration rule)
outer
outer shell
isoelectronic
ion
shell
electronic
inert gas
electrons
configuration
Se2– 18 4s 2 3d 10 4p 6
krypton
Br– 18
krypton
Rb+ 18
krypton
Sr2+ 18
krypton
Y3+ 18
krypton
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28. Ions Isoelectronic with Xenon2 4d 10 5p
ion
outer
shell
electrons
outer shell
electronic
configuration
isoelectronic
inert gas I– 18 6
xenon
Cs+
Ba2+
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29. Electron Affinity F(g) + e– ® F– (g)
The tendency of an atom or anion to pick up
excess electron density is a measure of the
electron affinity of that atom.
F(g) + e– ® F– (g)
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30. Electron Affinity Atoms which need a few electrons to attain
an outer shell inert gas electronic configuration
have high electron affinity.
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31. Electron Affinity Atoms which tend to lose electrons to attain
outer shell inert gas electronic configuration
have low electron affinity.
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32. Electron Affinity (EA)
The first electron affinity of an atom usually is
exothermic (releases energy).
O(g) + e– ® O–(g)
Why does the second electron affinity always
require energy?
O–(g) + e– ® O2– (g)
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33. Electronegativity (EN)
Relative measure of the tendency of an atom to gain an electron or share an electron with another atom.
Electronegativity is calculated, not measured.
One definition is EN = (IP + EA) / 2
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34. Electron Affinity and Electronegativity
Increases
from the bottom to the top
from the left to the right
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35. Hydrogen Is Electronegative
Where would hydrogen belong in the periodic table,
if the table was organized by period and electronegativity?
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36. End of Part 2 Be sure to review the Exam II Objective Sheet
You may use on the exam Concept Maps
(web diagrams) to help relate descriptive
chemistry material from the text reading.
Fine, Beall & Stuehr Pg and Pg
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