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Lewis Formulas
Copyright D. Herrick |
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20 Questions from past exams.
Practice for speed. Aim
for 2 minutes per problem.
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| 1. |
The
Lewis formula for the chlorine molecule shows |
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| A) |
a
single covalent bond |
| B) |
a
double covalent bond |
| C) |
a
triple covalent bond |
| D) |
a
single ionic bond |
| E) |
a
total of 16 valence electrons |
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| 2. |
The
Lewis formula for the nitrogen molecule shows |
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| A) |
a
single covalent bond |
| B) |
a
double covalent bond |
| C) |
a
triple covalent bond |
| D) |
a
single ionic bond |
| E) |
a
total of 16 valence electrons |
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| 3. |
In
the Lewis formula :C:::O: oxygen has |
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| A) |
oxidation
number = +2, formal charge = +1 |
| B) |
oxidation
number = +2, formal charge = -1 |
| C) |
oxidation
number = -2, formal charge = 0 |
| D) |
oxidation
number = -2, formal charge = +1 |
| E) |
oxidation
number = -2, formal charge = -1 |
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| 4. |
In
the Lewis formula :C:::O: carbon has |
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| A) |
oxidation
number = -2, formal charge = -1 |
| B) |
oxidation
number = -2, formal charge = +1 |
| C) |
oxidation
number = +2, formal charge = 0 |
| D) |
oxidation
number = +2, formal charge = +1 |
| E) |
oxidation
number = +2, formal charge = -1 |
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| 5. |
In
the Lewis formula oxygen has
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| A) |
oxidation
number = -2, formal charge = -2 |
| B) |
oxidation
number = -2, formal charge = 0 |
| C) |
oxidation
number = -1, formal charge = -1 |
| D) |
oxidation
number = -1, formal charge = 0 |
| E) |
oxidation
number = +1, formal charge = 0 |
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| 6. |
The
Lewis formula for CO2 shows |
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| A) |
two
double bonds |
| B) |
two
resonance bonds with bond order 1.5 each |
| C) |
two
single bonds |
| D) |
one
single bond and one double bond |
| E) |
one
single bond and one triple bond |
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| 7. |
The
bond order of the C-N bond in HCN is |
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| A)
0 |
B) 1 |
C)
1.5 |
D)
2 |
E)
3 |
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| 8. |
The
average bond order of the bonds in O3
is |
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| A)
0 |
B)
1 |
C)
1.5 |
D)
2 |
E)
2.5 |
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Complete
the Lewis structure and answer questions 9-16:
F
N
O
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| 9. |
The
total number of valence electrons is |
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| A)
24 |
B) 22 |
C)
20 |
D)
18 |
E) 16 |
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| 10. |
The
bond order between N and O is: |
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| A)
1 |
B)
1.5 |
C)
2 |
D)
2.5 |
E)
3 |
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| 11. |
The
number of lone pairs of valence electrons on N is |
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| 12. |
The
bond order between N and F is |
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| A)
1 |
B)
1.5 |
C)
2 |
D)
2.5 |
E)
3 |
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| 13. |
The
number of lone pairs of valence electrons on O is |
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| 14. |
The
formal charge on O is |
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| A)
+2 |
B)
-2 |
C)
+1 |
D)
-1 |
E)
0 |
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| 15. |
The
formal charge on N is |
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| A)
0 |
B)
-1 |
C)
+1 |
D)
-2 |
E)
+2 |
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| 16. |
The
oxidation number on N is |
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| A)
+1 |
B)
-1 |
C)
0 |
D)
+3 |
E)
-3 |
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| 17. |
Which
of these violate the octet rule?
| 1) SF2 |
2) [AlF6]3- |
3) PCl5 |
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| A) |
1
and 3 only |
| B) |
2
and 3 only |
| C) |
1
and 2 only |
| D) |
2
only |
| E) |
1,
2, and 3 |
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| 18. |
The
correct order of increasing carbon-carbon bond lengths
is |
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| A) |
H3CCH3
< H2CCH2
< HCCH |
| B) |
H3CCH3
< HCCH
< H2CCH2 |
| C) |
H2CCH2
< H3CCH3
< HCCH |
| D) |
HCCH < H2CCH2
< H3CCH3 |
| E) |
H2CCH2
< HCCH
< H3CCH3 |
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| 19. |
The
formal charge at chlorine in this Lewis formula is |
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| A)
+1 |
B)
+2 |
C)
0 |
D)
+3 |
E)
-1 |
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| 20. |
The
number of lone pairs of electrons on the central N atom
in nitryl chloride, NO2Cl, is |
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