Chemistry: Exam 3 Review

Carbon monoxide has ten bonding electrons and four antibonding electrons. Therefore,
it has a bond order of
A. 3
B. 7
C. 1
D. 5/2
E. 2

Carbon monoxide has ten bonding electrons and four antibonding electrons. Therefore,
it has a bond order of
A. 3
B. 7
C. 1
D. 5/2
E. 2

A

Antibonding molecular orbitals are produced by
A. constructive interaction of atomic orbitals.
B. destructive interaction of atomic orbitals.
C. the overlap of the atomic orbitals of two negative ions
D. all of these
E. none of these

B

What does bond order refer to?
A. How many bonds there are between two atoms
B. How many electrons each atom shares.
C. How many electrons each atom shares or absorbs
D. How many bonds each atom makes

A

Below is the molecular orbital diagram for a diatomic molecule. How many bonds are
formed between the atoms of the diatomic molecule, i.e, what is its bond order?
A. 0
B. 1
C. 2
D. 3

D

Which of the following is true about the valence electrons in metallic structures?
A. They are shared between the atoms
B. They are transferred from one atom to another atom.
C. They are delocalized over the entire collection of metal ions.
D. They are localized on a single atom

C

Below is the molecular orbital diagram for a diatomic molecule. The diagram indicates
that _______.
A. the bond order for the diatomic molecule is 2
B. the diatomic molecule is paramagnetic
C. the diatomic molecule is diamagnetic
D. only one bond is formed between the two atoms making up the diatomic molecule

C

Why can metals be beaten and bent into different shapes?

A. Because the bonding between metal cations is strong and cannot break.
B. Because the layers of metal cations can glide over one another as the sea of electrons acts as a sliding pad.
C. Because the valence electrons in metals are free to move about the structure.
D. Because valence electrons carry charge over the entire metal.

B

Why can metals conduct electricity?
A. In a metal, valence electrons are delocalized, mobile, and not associated with any
particular atom.
B. The sea of electrons surrounding the metal cations acts as a cushion.
C. The free electrons can absorb photons and re-emit them at the same frequency
that the light hits the surface.
D. The valence electrons are localized on particular atoms.

A

Which of the following describes metallic bond?
I. Electrostatic interactions between positively and negatively charged ions.
II. Attractive force between a metal and a nonmetal
III. Attraction between positively charged metal atoms and a sea of delocalized electrons
IV. Attractive force between two nonmetals
V. Electrons pairs are shared between atoms.
VI. Attractive force between two metal atoms.

B

Diamond and graphite are allotropes of carbon. Consider the representations of
diamond and graphite below.
Which of the following statements is consistent with those representations?
I. Because the hybridization of carbon in diamond is sp2, there is a network of pi
orbitals over the entire structure.
II. Graphite is slippery because the carbon sheets are held together only by London
dispersion forces thereby, they can slide over each other.
III. Diamond conducts electricity because there is large “band gap” between
the bonding and antibonding orbitals
IV. Diamond does not conduct electricity because the electrons are localized in
bonds between the atoms.
V. Graphite conducts electricity because pi orbitals form a network of pi bonds
over the whole structure that allows electrons to move freely.

C

Draw the Lewis structure for NCl3. Are there lone pairs on the nitrogen atom? How
many?
A. Yes, 3
B. No, 0
C. Yes, 2
D. Yes, 1

D

Draw the Lewis structure for C2F

What is the total number of sigma bonds and pi bonds in the
molecule?
A. 1 sigma bond and 1 pi bond
B. 2 sigma bonds and 1 pi bond
C. 3 sigma bonds and 2 pi bonds
D. 4 sigma bonds and 0 pi bonds

C

Consider the molecules represented below.
Which of the following statements is true?
I. The structures represent structural isomers
II. The structures represent different molecules that
are not isomers. because
III. They have the same chemical formula but different connections between atoms (different
connectivity).
IV. They have different number and types of atoms

C

Pi bonds are formed by .
A. Side-to-side overlap of s orbitals
B. Side-to-side overlap of p orbitals
C. End-to-end overlap of s orbitals
D. End-to-end overlap of p orbitals

B

Which of the following statements about sigma and pi bonds is (are) correct?
I. In a sigma bond the regions of orbital overlap lie on opposite sides of the internuclear axis.
II. In a pi bond there is a plane with no probability of finding an electron (node)
III. All single bonds are sigma bonds
IV. A double bond consists of two pi bonds
A. I and II
B. II and III
C. III and IV
D. I and IV

B

The drawings below represent .
I. Cis-trans Isomers
II. Same compound
Because
III. If either representation is flipped over top to bottom, they are identical
IV. They have the same chemical formula but differ in the arrangement of atoms or groups
of atoms around the double bond.
V. Free rotation about the double bond results in the same structure.
A. II and V
B. I and IV
C. I and V
D. II and III

B

Consider the figure below. Which of the following statements is true?
I. Two s orbitals overlap to produce a sigma bond
II. Two s orbitals overlap to produce a pi bond
III. Two p orbitals overlap end-to-end to produce a sigma bond
IV. Two p orbitals overlap side-by-side to produce a pi bond
A. I and III
B. II and IV
C. I only
D. IV only

A

Consider the structure below. How many sigma bonds are there in bond indicated by arrow 2?
A. 0
B. 1
C. 2
D. 3

B

Consider the structure below. What are the hybridization, shape, and bond angle for the
carbon atom indicated by arrow a?
A. sp, linear, 180º
B. sp², trigonal planar, 120º
C. sp³, tetrahedral, 109.5º
D. sp³d, trigonal pyramidal, 120º, 180º

B

Below is a representation of the structure of butadiene. How many sigma and pi bonds are
contained in this moXlecule?
A. 7 sigma bonds and 2 pi bonds
B. 6 sigma bonds and 4 pi bonds
C. 9 sigma bonds and 2 pi bonds
D. 9 sigma bonds and 4 pi bond

C

Below is the Lewis structure for ethanol. How many sigma and pi bonds are contained in this
molecule?
A. 4 sigma bonds and 8 pi bonds
B. 8 sigma bonds and 2 pi bonds
C. 6 sigma bonds and 2 pi bonds
D. 8 sigma bonds and 0 pi bonds

D

The Lewis structure for ClCN is below. Valence bond theory predicts that carbon will use
_________ hybrid orbitals in ClCN

A. sp
B. sp²
C. sp³
D. sp³d
E. sp³d²

A

The Lewis structure for CO 2- is below. Valence bond theory predicts that carbon will use hybrid
orbitals in CO3²-

A. sp
B. sp²
C. sp³
D. sp³d
E. sp³d²

B

The Lewis structure for SO 2 is below. There are electron
regions (centers) around the central atom S; therefore, S uses hybrid
orbitals in SO 2.

A. 2, sp
B. 3, sp²
C. 4, sp³
D. 5, sp³d
E. 6, sp³d²

B

What is the molecular polarity of NCl 3 and why?
A. It is polar because its charges are distributed asymmetrically, and its
geometric shape is asymmetrical.
B. It is nonpolar because its charges are distributed symmetrically, and its
geometric shape is symmetrical.
C. It is polar because its charges are distributed symmetrically, and its geometric shape is
symmetrical
D. It is nonpolar because its charges are distributed asymmetrically, and its
geometric shape is asymmetrical.

A

London dispersion forces are attractive forces between .
A. an ion and a permanent dipole
B. a transient dipole and an induced dipole
C. two permanent dipoles
D. two molecules with hydrogen covalently bonded to an oxygen atom.

B

A nonpolar covalent bond will form between two atoms of electronegativities.
A. different, opposite
B. identical, different
C. different, different
D. identical, equal

D

Which of the following molecules is polar?
I. CH 4
II. HCN
III. CH 3COCH 3
IV. SO3
A. I and III
B. II and III
C. II and IV
D. I and IV

B

The molecule CH 2Br 2 is because
A. polar, the sum of the bond dipoles results in a molecular dipole different from zero.
B. nonpolar, the sum of the bond dipoles results in molecular dipole equal to zero
C. nonpolar, it does not have any bond dipoles.
D. polar, the sum the bond dipoles results in molecular dipole equal to zero.

A

lectronegativity is inversely proportional to atomic size. Carbon (C) is
electronegative than Boron (B) because
A. More, carbon has a larger atomic radius than boron; therefore, less ability to attract
electrons to itself in a bond.
B. Less, carbon has a smaller atomic radius than boron; therefore, less ability to attract
electrons to itself in a bond.
C. More, carbon has a smaller atomic radius than boron; therefore, more ability to attract
electrons to itself in a bond.
D. Less, carbon has more electrons than boron

C

What type of attractive force is indicated by the arrow?
A. Covalent bond
B. London dispersion forces
C. Hydrogen bonding
D. Dipole-dipole

D

What type of attractive force is indicated by the arrow.
A. Covalent bond
B. London dispersion forces
C. Hydrogen bonding
D. Dipole-dipole

A

Dashed lines are used in the figure below to represent interactions between three
methylamine molecules. Which roman numeral is matched to the representation of hydrogen
bonding interactions?
A. I
B. II
C. III
D. All of them

C

Which of the following compound is expected to have the lowest melting point?
I. KCl
II. MgS
III. SrO
IV. RbCl
A. KCl because it has the smallest lattice energy
B. MgS because the charge on the ions is larger than those on KCl and RbBr
C. SrO because the greater the charge on the ions, the smaller the lattice energy.
D. RbBr because the charges on the ions are smaller than those in MgS and SrO, and the
ions are farther apart than the ions in KCl.

D

What is the chemical formula for the ionic compound that contains Fe 3+ and SO42- ions?
A. FeSO4
B. Fe2(SO4) 3
C. Fe3(SO4) 2
D. Fe2
(SO4) 3

B

Which of the following statements about ionic and metallic
compounds is correct?
I. Metals conduct electricity because the electrons are not fixed
between atoms.
II. Ionic compounds in the solid-state conduct electricity because the electrons are free to
move.
III. Ionic compounds in the liquid state conduct electricity because the ions are free to move.
A. I only
B. II and III
C. III only
D. I and III

D

What is the formal charge for the nitrogen atom in the Lewis structure below?
A. +3
B. 0
C. +5
D. +1

D