Chapter 1
MULTIPLE CHOICE QUESTIONS Part 1: Struktur, Bindning
(Answers on page 14)
Chapter 1
Topic: Lewis Structures, Formal Charges
5. Listed below are electron dot formulas for several simple molecules and ions. All
valence electrons are shown; however, electrical charges have been omitted deliberately.
H : Be : H
H
..
H:B:H
..
H
H
..
H:N:H
..
H
..
H:N:H
..
H
H
..
H:O:H
..
I
II
III
IV
V
Topic: Atomic Orbitals, Molecular Orbitals Hybridization
1. When the 1s orbitals of two hydrogen atoms combine to form a hydrogen molecule,
how many molecular orbitals are formed?
A) 1
B) 2
C) 3
D) 4
E) 5
2. When the ls orbitals of two hydrogen atoms combine to form a hydrogen molecule,
which molecular orbitals are formed?
A) One bonding molecular orbital only
B) Two bonding molecular orbitals
C) One bonding molecular orbital and one antibonding molecular orbital
D) Two antibonding molecular orbitals
E) Three bonding molecular orbitals
3. The following electron configuration represents _______.
A)
B)
C)
D)
E)
4.
A)
B)
C)
D)
E)
1s
2sp3 2sp3 2sp3 2sp3
the ground state of boron.
the sp3 hybridized state of carbon.
the sp3 hybridized state of nitrogen.
the ground state of carbon.
an excited state of carbon.
A)
B)
C)
D)
E)
Which of the structures actually bear(s) a positive charge?
I
II
III
III & V
IV & V
6. What is the formal charge on oxygen in the following structure?
..
H3C
O
CH3
CH3
A)
B)
C)
D)
E)
+2
+1
0
-1
-2
7. In which structure(s) below does the oxygen have a formal charge of +1?
H
..
O
H
H
..
O:
..
1
I
I only
II only
I and III
I and IV
I, III, and IV
s
A)
B)
C)
D)
E)
..
C
O
H
H
Identify the atomic orbitals in the C-C sigma bond in ethyne.
(2sp2, 2sp2)
(2sp3, 2sp3)
(2sp, 2sp)
(2p, 2p)
(2sp, 1s)
H
2
H3C
..
O
CH3
III
II
H
IV
CH3
Chapter 1
Chapter 1
8. Which structure(s) contain(s) an oxygen that bears a formal charge of +1?
..
..
:O
:O
..
..
..
..
: O C O:
H C
H3C
O
H
H3C
O
CH3
C
:O
:
:
:
: O
O
..
..
..:
H
CH3
I
II
III
IV
V
A)
B)
C)
D)
E)
I and II
III and IV
V
II
I and V
D) All of these
E) None of these
12. Which is NOT a correct Lewis structure?
..
A) H N F :
..
9. Which of the following molecules or ions has a nitrogen with a formal charge of -1?
(Charges on ions have been omitted.)
..
A) : N H
H
B) H
..
N
D) H3C
E) H3C
N
..
C) H
.H.
O
..
H
N
CH3
H
C
N:
N
CH2
I
..
.O.
..
F:
..
..
O
H
. .. .
:O H
B
:O
.. H
E) None of these
H3C
..
N
..
H
H
H
..
N
..
.OH
.
H3C
..
NH2
H
A)
B)
C)
D)
E)
C
D)
CH3
13. Listed below are electron dot formulas for several simple molecules and ions. All
valence electrons are shown; however, electrical charges have been omitted deliberately.
10. In which structure(s) below does nitrogen have a formal charge of +1?
H3C
H
H
..
H
H
H
B)
H
C) H
Topic: Lewis Structures, Formal Charges
11. Which of the following is an ion with a single negative charge?
..
A) H3C O :
.. .. ....
B) : O N O :
..
..
C)
: O:
..
:O N
:O
..:
H3C
..
N
CH3
II
III
I
II and IV
III and V
I and V
V
IV
H
..
H:B:H
..
H
H
..
H:N:H
..
H
..
H:N:H
..
H
H
..
H:O:H
..
I
II
III
IV
V
V
A)
B)
C)
D)
E)
3
H : Be : H
CH3
Which of the structures is negatively charged?
I
II
III
IV
V
4
Chapter 1
Chapter 1
Topic: Lewis Structures, Formal Charges
Topic: Lewis Structures, Formal Charges Molecular Geometry
14. Which compound contains a nitrogen atom with a formal positive charge?
A)
B)
C)
D)
E)
N
H
N
N
I
II
III
I
II
III
More than one of the above
None of the above
15. In which of these cases does the central atom have a zero formal charge?
A) HFH
H
B)
C)
H3C O
F
F
B
F
D)
H3C
CH3
F
H
N
CH3
H
CH3
E)
H3C
C
CH3
CH3
16. The formal charge on sulfur in sulfuric acid is:
O
H O
S
O H
17. Expansion of the valence shell to accommodate more than eight electrons is possible
with:
A) Fluorine
B) Nitrogen
C) Carbon
D) Sulfur
E) Beryllium
18.
A)
B)
C)
D)
E)
Based on VSEPR theory, which of the following would have a trigonal planar shape?
CH3)3N
HCN
NH4+
CH3!
CH3+
19.
A)
B)
C)
D)
E)
What shape does the methyl cation, CH3+, have?
Octahedral
Tetrahedral
Trigonal planar
Linear
Trigonal pyramidal
20.
A)
B)
C)
D)
E)
What bond angle is associated with a tetrahedral molecule?
120°
109.5°
180°
90°
45°
21.
A)
B)
C)
D)
E)
What would be the spatial arrangement of the atoms of the methyl anion, :CH3-?
Octahedral
Tetrahedral
Trigonal planar
Linear
Trigonal pyramidal
22.
A)
B)
C)
D)
E)
Which of these structures would be a perfectly regular tetrahedron?
CH3Br
CH2Br2
CHBr3
CBr4
More than one of these
O
A)
B)
C)
D)
E)
0
-1
+1
-2
+2
5
6
Chapter 1
Topic: Periodic Properties, Electronegativity
23.
A)
B)
C)
D)
E)
Chapter 1
Topic: Atomic Orbitals, Bonding
Select the most electronegative element.
H
O
N
B
C
28.
A)
B)
C)
D)
E)
Topic: Atomic Orbitals, Hybridization
Which of these substances contains both covalent and ionic bonds?
NH4Cl
H2O2
CH4
HCN
H2S
Topic: Atomic Orbitals, Periodic Trends, Electronegativity
3
24.
A)
B)
C)
D)
E)
In which molecule is the central atom sp hybridized?
CH4
NH3
H2O
All of these
None of these
25.
A)
B)
C)
D)
E)
Which compound has the shortest carbon-carbon bond(s)?
CH3CH3
CH2=CH2
HC"CH
CH3CH2CH3
All carbon-carbon bonds are the same length.
26.
A)
B)
C)
D)
E)
Which of the following contains an sp2-hybridized carbon?
CH4
CH3:!
CH3CH3
CH3+
HC"CH
27. Which is the shortest of the carbon-carbon single bonds indicated by arrows in the
following compounds?
A)
29.
A)
B)
C)
D)
E)
The greatest degree of ionic character is anticipated for the bond between:
H and C
H and Cl
C and Cl
H and Br
Br and Cl
Topic: Atomic Orbitals, Hybridization
30.
A)
B)
C)
D)
Which molecule contains an sp-hybridized carbon?
HCN
CH2=CH2
CH3Cl
H
C O
H
E) CH3CH3
Topic: Atomic Orbitals, Lewis structures, Resonance
31. Which of the structures below is not expected to contribute to the CO2 resonance
hybrid?
A)
O
C
O
C
C
O
O
H3C
CH3
B) O
C) O
D)
H3C
C
E)
H3C
CH
B)
C)
O
CH
CH2
O
C
C
O
O
D)
HC
C
C
CH
E) H2C
HC
C CH
7
8
Chapter 1
Chapter 1
Topic: Atomic Orbitals, Lewis Structures, Resonance
Topic: General
36. Credit for the first synthesis of an organic compound from an inorganic precursor is
usually given to:
A) Berzelius
B) Arrhenius
C) Kekule
D) Wohler
E) Lewis
:
..
C
O
H 3C
N
:
:
Topic: Isomerism
37. CH3CH2OCH2CH3 and CH3CH2CH2CH2OH are examples of what are now termed:
A) Structural isomers
B) Resonance structures
C) Functional isomers
D) Empirical isomers
E) Constitutional isomers
.
C)
..
..
and
:
O
..
C
..
O
:
:
:
B)
:
:
O
:
:
:
32. Which of the following pairs are NOT resonance structures?
A)
and
H 3C O N O :
H 3C O N O :
:
:
O
N
O
:
..
.
:
H 3C
O
and
:
..
:
..
O
D) Each of these pairs represents resonance structures.
E) None of these pairs represents resonance structures.
Topic: Empirical and Molecular Formulas
33.
A)
B)
C)
D)
E)
What is the empirical formula for cyclohexane? (Its molecular formula is C6H12.)
CH
CH2
C2H4
C6H6
C2H2
34. A compound consists only of carbon, hydrogen and oxygen. Elemental analysis gave:
C, 70.5%, H, 13.8%. The molecular weight of the compound was found to be 103 +/- 3.
What is the molecular formula for the compound?
A) C6H12O
B) C5H12O2
C) C3H2O4
D) C3H6O3
E) C6H14O
Topic: Isomerism
Br
I
A)
B)
C)
D)
E)
Br
Topic: Lewis structures, Hybridization
39. Which molecule has a non-linear structure (i.e., for which molecule are the nuclei not in
a straight line)?
A) O=C=O
B) H–O–H
C) H–Cl
D) H–C"N
E) H–C"C–H
Topic: Isomerism
40. Which of the following structures represent compounds that are constitutional isomers
of each other?
35. Which of the following is a set of constitutional isomers?
Br
Topic: Hybridization
38. What is the approximate hybridization state of the oxygen molecule in ethanol,
C2H5OH?
A) sp
B) sp2
C) sp3
D) p3
E) d2sp3
Br
II
III
I and II
II and III
I, II, and III
II, III, and IV
I, III, and IV
IV
A)
B)
C)
D)
E)
9
I
I and II
I and III
I, II, and III
I, II, III, and IV
II and III
II
III
10
IV
Chapter 1
Chapter 1
Topic: Isomerism
Topic: Isomerism
41. Which compound is not an isomer of the others?
OH
O
O
OH
A)
B)
C)
D)
E)
I
II
III
I
II
III
IV
All of the above are isomers of each other.
IV
44. Which of the following represent a pair of constitutional isomers?
A)
and
B) CH3CH=CH2 and CH2=CHCH3
Br
Br
C)
Br
H
H
and Br
H
Br
D)
H
Br
H
Br
and
H
H
H
A)
B)
C)
D)
E)
Br
E) More than one of these
42. Consider the following:
CH3CH2CH=CHCH2CH3
I
CH3CH2CH2CH2CH=CH2
II
CH3CH=CHCH2CH2CH3
III
CH2=CHCH2CH2CH2CH3
IV
Which two structures represent the same compound?
I and II
II and III
I and III
II and IV
None of these
45.
A)
B)
C)
D)
E)
Cis-trans: isomerism is possible only in the case of:
CH2=CBr2
CH2=CHBr
BrCH=CHBr
Br2C=CHBr
Br2C=CBr2
Topic: Atomic Orbitals, Hybridization, Bonding
46. Identify the atomic orbitals involved in the C-2---C-3 sigma bond (indicated by an
arrow) in the following molecule:
1
4
43. Consider the following:
2
6
CH3CH2CH2CH=CHCH2CH2CH3
I
A)
B)
C)
D)
E)
CH3CH2CH2CH2CH2CH2CH=CH2
II
CH3CH2CH=CHCH2CH2CH2CH3
CH2=CHCH2CH2CH2CH2CH2CH3
III
IV
Which structures can exist as cis-trAns: isomers?
I and II
I and III
I and IV
II and III
I alone
11
7
A)
B)
C)
D)
E)
sp2, sp2
sp2, sp
sp2, sp3
sp3, sp2
sp, sp2
5
3
Topic: Molecular Geometry
47. Based on the VSEPR theory, which of the following would have a tetrahedral
arrangement of electrons around the central atom?
A) BH3
B) NO2 !
C) SiH4
D) CO3 2!
E) SO3
12
Chapter 1
Chapter 1
Topic: Periodic Trends, Electronegativity
48.
A)
B)
C)
D)
E)
Svar: Part 1: Struktur, Bindning
Select the least electronegative element
P
N
Mg
Si
K
Topic: Atomic Orbitals, Hybridization
49. In which molecule(s) can the molecular geometry be attributed to an sp2 hybridized
central atom?
A) PBr3
B) CH4
C) CHCl3
D) HNO2
E) None of the above has an sp2 hybridized central atom
Topic: Bonding, Atomic Orbitals, Hybridization
50. Which molecule has the shortest carbon-carbon single bond?
I
A)
B)
C)
D)
E)
I
II
III
IV
V
II
III
IV
V
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