Chapter 8 Test Study Guide
AP Chemistry
6 points
DUE AT TEST (Thurs., 12/12/13)
Name: _______________________________
Date: _______________________________
Topics to be covered on the December 12, 2013 test:
bond
bond energy
ionic bond
covalent bond
polar covalent bond
electronegativity (no table provided)
ä
bond polarity
polar/dipolar/dipole moment
ionic radius
ionic radius trend
ion (prediction of charge)
cation
anion
isoelectronic
Lewis structures
duet rule
octet rule (and exceptions to it)
bonding pair
shared pair
lone pair (unshared pair)
single bond
double bond
triple bond
endothermic
exothermic
breaking bonds
making bonds
resonance
delocalization
VSEPR
VSEPR shapes
formal charge
calculation of enthalpy of reaction using bond energy tables
lattice energy
1)
Explain the following variations in radius:
(a) I- > I > I+ (all have the same p+; I+ lost an e-, so p+ pull more and make it smaller)
(b) Ca2+ > Mg2+ > Be2+ (same group; Ca2+ has more energy levels)
(c) Fe > Fe2+ > Fe3+ (Fe3+ has lost more electrons)
2)
Place F, Br, and Br - in order of decreasing size. (Br - Br F)
3)
(a) What is an isoelectronic series? (sequence of ions with the same number of e-)
(b) Which neutral atom is isoelectronic with each of the following ions?
Ga3+ (Ni)
Zr4+ (Kr)
Mn7+ (Ar)
I- (Xe)
Pb2+ (Hg)
4)
Identify at least two ions that have the following ground-state electron configurations:
(a) [Ar] (P3-, S2-, Cl-, K+, Ca2+)
(b) [Ar]3d5 (Fe3+, Mn2+)
(c) [Kr] 5s24d10 (Sn2+, In+)
5)
Consider S, Cl, K, and their most common ions.
(a) List the atoms in terms of increasing size. (Cl S K)
(b) List the ions in order of increasing size. (K+ Cl- S2-)
(c) Explain any differences in the orders of the atomic and ionic sizes.
K = more energy levels, so larger than Cl or S
K+, S2-, Cl- are isoelectronic; S2- has gained the most e-, so it is the largest
6)
For each of the following sets of atoms and ions, arrange the members in order of increasing
size:
(a) Se2-, Te2-, Se (Se < Se2- < Te2-)
(b) Co3+, Fe2+, Fe3+ (Fe3+ < Fe2+ and Co3+ < Fe3+)
[I WILL NOT ASK ONE THIS DIFFICULT]
(c) Ca, Ti4+, Sc3+ (Ti4+ < Sc3+ < Ca)
(d) Be2+, Na+, Ne (Be2+ < Na+ < Ne)
7)
Does the lattice energy of an ionic solid increase or decrease
(a) as the charges on the ions increase? (increase)
(b) as the sizes of the ions increase? (decrease)
(c) Arrange the following substances according to their expected lattice energies
(from lowest lattice energy to highest):
MgS, KI, GaN, LiBr (KI, LiBr, MgS, GaN)
8)
Explain the following trends in lattice energy:
(a) NaCl > RbBr > CsBr (NaCl = smallest ions)
(b) BaO > KF (BaO = higher charges than KF)
(c) SrO > SrCl2 (SrO = higher charges than Sr2+ and Cl-)
9)
Using only a periodic table, select the most electronegative atom in each of the following sets
(then check yourself with a table):
a)
Na, Mg, K, Ca
b)
Be, B, C, Si
c)
P, S, As, Se
d)
Zn, Ge, Ga, As
10)
Arrange the following sets of bonds in order of increasing polarity:
a) C–F, O–F, Be–F
b) O–Cl, S–Br, C–P
(O–F, C–F, Be–F)
(S–Br, C–P, O–Cl)
c) S–C, B–F, N–O
(S–C, N–O, B–F)
Rank the following bonds in order of INCREASING ionic character (from most covalent to
most ionic):
N–O, Ca–O, C–F, Br–Br, K–F
(Br–Br, N–O, C–F, Ca–O, K–F)
11)
12)
Draw the Lewis structures for each of the following. Then predict the bond angles and
VSEPR shape:
a)
HF
linear 180°
g)
N2
l)
NH3
r)
CH4
linear 180°
trigonal pyramid
tetrahedral
b)
CF4
h)
NO+
m)
HCN (central atom is carbon)
(tetrahedral like
[:N/O:]+
H-C/N:
methane)
linear 180°
linear 180°
c)
i)
PH3
trigonal pyramid 107°
d)
CHCl3
tetrahedral 109.5°
H2CO (central atom is carbon)
NH4+
n)
s)
O2
tetrahedral 109.5°
o)
SeF2
trigonal planar 120°
linear 180°
t)
HBr
bent
104.5°
e)
POCl3
tetrahedral
f)
PO43-
tetrahedral
s)
SeCl6
octahedral
13)
SO42-
j)
p)
tetrahedral
k)
SO32-
XeO4
ICl5
u)
tetrahedral
q)
trigonal pyramid
t)
linear 180°
ClO2-
bent
u)
square pyramid (not on test)
TeF4
see-saw
Write the electron configurations for
a) the cations Sr2+, Cs+, Pb2+, and In+
[Kr] [Xe] [Xe]6s25d10 [Kr]5s24d10
b) the anions P3-, Br-, and S2- [Ar] [Kr] [Ar]
ClO4-
tetrahedral
r)
PCl5
trigonal bipyramidal
v)
PCl3
trigonal pyramid
14)
Which of the following ions have noble gas electron configurations?
a) Fe2+, Fe3+, Sc3+, Co3+
b) Tl+, Te2-, Cr3+
d) Ba2+, Pt2+, Mn2+
c) Pu4+, Ce4+, Ti4+
15)
Which noble gas has the same electron configuration as each of the ions in the following
compounds?
a) cesium sulfide
b) strontium fluoride
[Xe]
[Ar]
[Kr]
[Ne]
c) calcium nitride
[Ar]
[Ne]
16)
d) aluminum bromide
[Ne]
[Kr]
For each of the following groups, place the atoms and ions in order of DECREASING size:
a) Cu, Cu+, Cu2+
b) Ni2+, Pd2+, Pt2+
(Cu > Cu+ > Cu2+)
(Pt2+ > Pd2+ > Ni2+)
c) O, O-, O2-
d) La3+, Eu3+, Gd3+, Yb3+
(O2- > O- > O)
e) Te2-, I-, Cs+, Ba2+, La3+
(Te2- > I- > Ba2+ > La3+)
17)
Predict the empirical formulas of the ionic compounds formed from the following pairs of
elements.
a) Al and F
b) K and S
c) Y and O
d) Mg and N
AlF3
K2S
YO or Y2O3
Mg3N2
d) Ba and F
BaF2
18)
(La3+ > Eu3+ > Gd3+ > Yb3+)
e) Cs and Cl
CsCl
f) Li and N
Li3N
g) Al and O
Al2O3
Use the bond energy tables to estimate ÄH for each of the following reactions in the gas
phase:
(a) H2 + Cl2 —> 2 HCl [-183 kJ]
(b) N/N + 3 H2 —> 2 NH3 [-109 kJ]
19)
Use the bond energy tables to predict ÄH for the isomerization of methyl isocyanide to
acetonitrile:
CH3N/C (g) —> CH3C/N (g)
[-42 kJ]
20)
Use bond energies to predict ÄH for the combustion of ethyl alcohol. [-1276 kJ]
21)
Use bond energies to estimate ÄH for the following reaction:
H2O2 (aq) + CH3OH (aq) -----> H2CO (aq) + 2 H2O (R)
22)
[-295 kJ]
(a) What is the trend in electronegativity going from left to right in a row on the periodic
table? (increases)
(b) How do electronegativity values generally vary going down a column on the periodic
table? (decrease)
(c) How do the periodic trends of first ionization energy and atomic radius relate to
electronegativity? (FIE follows EN trend, atomic radius is opposite EN trend)
23)
What is the difference between an ionic bond and a polar covalent bond?
(ionic = transfer of electron, most polar; polar covalent = unequal sharing of e-)
24)
Which has the largest dipole moment, an ionic bond, a covalent bond, or a polar covalent
bond? (ionic)
25)
p. 398 # 119 (see book for answer)
26)
p. 398 #117 (see book for answer)
27)
p. 398 #115 (see book for answer)
28)
p. 397 #97 (see book for answer)
29)
p. 397 #101 (see book for answer)
30)
p. 397 #92 (resonance –> draw the three structures!)
31)
p. 393 #25 (see book)
32)
p. 393 #26 c = true; A = XeCl2 is linear; B = SO2 angle is larger than SCl2 but smaller than
CS2; D = MINIMIZE repulsions!
33)
p. 402-A
1) __C__
2) __D__
12) __A__
13) __B__
3) __A__
4) __B__
8) __D__
11) __A__