AP Chemistry
Ch. 8 Practice Test
Name_______________________________________
*1) There are __________ paired and __________ unpaired electrons in the Lewis symbol for a phosphorus atom.
A) 4, 2
B) 2, 4
C) 2, 3
D) 4, 3
E) 0, 3
Answer: C Sec. 8.1
2) Based on the octet rule, magnesium most likely forms a __________ ion.
A) Mg 2+
B) Mg 2C) Mg6D) Mg6+
E) MgAnswer: A Sec. 8.1
*3) The electron configuration of the phosphide ion (P3- ) is __________.
A) [Ne]3s2
B) [Ne]3s2 3p1
C) [Ne]3s2 3p3
D) [Ne]3p2
E) [Ne]3s2 3p6
Answer: E Sec. 8.1
*4) For a given arrangement of ions, the lattice energy increases as ionic radius __________ and as ionic charge __________.
A) decreases, increases
B) increases, decreases
C) increases, increases
D) decreases, decreases
E) This cannot be predicted.
Answer: A Sec. 8.2
5) Elements from opposite sides of the periodic table tend to form __________.
A) covalent compounds
B) ionic compounds
C) compounds that are gaseous at room temperature
D) homonuclear diatomic compounds
E) covalent compounds that are gaseous at room temperature
Answer: B Sec. 8.2
*6) A __________ covalent bond between the same two atoms is the longest.
A) single
B) double
C) triple
D) They are all the same length.
E) strong
Answer: A Sec. 8.3
7) In the molecule below, which atom has the largest partial negative charge __________?
Cl
∣
F – C – Br
∣
I
A) Cl
B) F
C) Br
D) I
E) C
Answer: B Sec. 8.4
*8) The ability of an atom in a molecule to attract electrons is best quantified by the __________.
A) paramagnetism
B) diamagnetism
C) electronegativity
D) electron change-to-mass ratio
E) first ionization potential
Answer: C Sec. 8.4
9) Electronegativity __________ from left to right within a period and __________ from top to bottom within a group.
A) decreases, increases
B) increases, increases
C) increases, decreases
D) stays the same, increases
E) increases, stays the same
Answer: C Sec. 8.4
*11) The Lewis structure of HCN (H bonded to C) shows that __________ has __________ nonbonding electron pairs.
B) N, 1
C) H, 1
D) N, 2
E) C, 2
Answer: B Sec. 8.5
*40) The formal charge on nitrogen in NO3 - is __________.
A) C, 1
A) -1
B) 0
C) +1
D) +2
E) -2
Answer: C Sec. 8.5
*44) How many equivalent resonance forms can be drawn for CO32- - (carbon is the central atom)?
A) 1
B) 2
C) 3
D) 4
E) 0
Answer: C Sec. 8.6
*63) The type of compound that is most likely to contain a covalent bond is __________.
A) one that is composed of a metal from the far left of the periodic table and a nonmetal from the far right of the periodic table
B) a solid metal
C) one that is composed of only nonmetals
D) held together by the electrostatic forces between oppositely charged ions
E) There is no general rule to predict covalency in bonds.
Answer: C Sec. 8.3
65) Of the atoms below, __________ is the most electronegative.
A) Br
B) O
C) Cl
D) N
E) F
Answer: E Sec. 8.4
*69) Of the molecules below, the bond in __________ is the most polar.
A) HBr
B) HI
C) HCl
D) HF
E) H 2
Answer: D Sec. 8.4
*85) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) NF3
B) IF3
C) PF3
D) SbF3
E) SO42Answer: B Sec. 8.7
*89) A valid Lewis structure of __________ cannot be drawn without violating the octet rule.
A) ClF3
B) PCl3
C) SO3
D) CCl4
E) CO2
Answer: A Sec. 8.7
96) Of the bonds C–N, C=N, and C≡N, the C–N bond is __________.
A) strongest/shortest
B) strongest/longest
C) weakest/shortest
D) weakest/longest
E) intermediate in both strength and length
Answer: D
Diff: 1 Page Ref: Sec. 8.8
8  Bonding & Molecular Structure
PRACTICE TEST
1.
The correct Lewis symbol for ground state carbon is
a)
b)
c)
d)
e)
2.
The correct Lewis symbol for ground state aluminum is
a)
b)
c)
d)
e)
3.
Using the picture below, what process corresponds to the lattice energy?
a) 1
4.
b) 2
c) 3
d) 4
e) 5
Which of the following favors formation of an ionic compound?
a) low ionization energy for metal
b) high electron affinity for non metal
c) high lattice energy
d) all of a-c above
e) none of a-c above
5.
Which of the atoms below is least likely to violate the octet rule?
a) Be b) P
c) S
d) B
e) F
6.
How many electrons are shown in the Lewis structure of perchlorate ion, ClO4–?
a) 30
b) 31
c) 32
d) 50
e) 51
Questions7 - 9 refer to the following energy diagram:
7.
What is the energy of the two isolated atoms?
a) –400 J
d) 0.100 nm
b) –335 J
e) –155 J
c) 0 J
8.
What is the bond length of the bond between the two atoms?
a) 0.020 nm
d) 0.330 nm
b) 0.140 nm
e) 2.00 nm
c) 0.400 nm
9.
What is the bond energy (bond strength) of the bond?
a) 0 J
d) –330 J
b) –110 J
e) –422 J
c) –10 J
11. Which of the following is the correct Lewis structure for SOCl2? (Consider formal charge)
a)
d)
b)
e)
c)
14. Which of the following bonds is most polar?
a) N – Cl
d) Br – Br
b) C – N
e) S – O
c) S – S
15. Which one of the following molecules is a polar molecule?
a)
c)
b)
d)
19. The molecule BrF3 has how many lone pairs of electrons on the central atom?
a) 0
b) 1
c) 2
d) 3
24. Among those listed below, which element will have the strongest tendency to form double bonds?
a) S
b) B
c) Al
d) O
H
2.1
Li
1.0
Na
0.9
K
0.8
Rb
0.8
Cs
0.7
Fr
0.7
Electronegativity Values
Be
1.5
Mg
1.2
Ca
1.0
Sr
1.0
Ba
0.9
B
2.0
Al
1.5
Ga
1.6
In
1.7
Tl
1.8
C
2.5
Si
1.8
Ge
1.8
Sn
1.8
Pb
1.8
N
3.0
P
2.1
As
2.0
Sb
1.9
Bi
1.9
O
3.5
S
2.5
Se
2.4
Te
2.1
Po
2.0
F
4.0
Cl
3.0
Br
2.8
I
2.5
At
2.2
He
--Ne
--Ar
--Kr
--Xe
--Rn
---
Bonding & Molecular Structure
1.
STUDY QUESTIONS
Classify the following substances as covalent molecules or ionic compounds:
a. MgO
e. LiCl
b. NI3
f. SF4
c. CuS
g. XeF4
d. NO2
h. CsF
2.
How many valence electrons do the following atoms or ions have? Write their Lewis symbols.
a. Ca
e. Mg2+
b. S
f. C4c. P
g. Li
d. O2h. Ne
3.
Which of the following molecules do not obey the octet rule?
a. AlCl3
e. SF6
b. PCl3
f. BeCl2
c. PCl5
g. NO2
d. SiCl4
h. XeF4
4.
Order the following salts in increasing lattice energy?
CaS, MgO, KCl, CsI, NaF
5.
Draw Lewis electron dot structures for the following molecules.
a. NCl3
b. BCl3
c. ClO2d. SF4
e. OCS
f. SO2
6.
Assign formal charges to all the atoms in the following species:
a. chlorite ion ClO2b. hydroxylamine HONH2
c. phosphorous acid H3PO3
d. ozone O3
e. nitrogen dioxide NO2
7.
Estimate, using the bond energies+, the enthalpy change H° for the conversion of propene to
isopropanol:
CH3CH=CH2 + H2O  CH3CH(OH)CH3
8.
When ethanol burns in air, heat is released. Estimate the enthalpy of combustion of ethanol vapor H°
from the average bond energies. Use thermochemical data in Chapter 6 to calculate the same thing.
Compare the two values obtained.
9.
Draw possible resonance structures for
a. NO2b. HCO2c. NO2Cl