Chemistry Midterm Review Questions
Atoms, Molecules, Ions & Compounds
1) The nucleus of an atom contains __________.
A) electrons
B) protons, neutrons, and electrons
D) protons and electrons
E) protons
C) protons and neutrons
2) Potassium is a __________ and chlorine is a __________.
A) metal, nonmetal
B) metal, metal
C) metal, metalloid
D) metalloid, nonmetal
E) nonmetal, metal
3) Aluminum reacts with a certain nonmetallic element to form a compound with the general formula
AlX. Element X is a diatomic gas at room temperature. Element X must be __________.
A) oxygen
B) fluorine
C) chlorine D) nitrogen
E) sulfur
4) Predict the empirical formula of the ionic compound that forms from aluminum and oxygen.
A) AlO
B) Al3O 2 C) Al2 O3 D) AlO2 E) Al2 O
5) The correct name for SrO is __________.
A) strontium oxide
B) strontium hydroxide
D) strontium monoxide
E) strontium dioxide
C) strontium peroxide
6) The name of PCl3 is __________.
A) potassium chloride
B) phosphorus trichloride
D) monophosphorous trichloride E) trichloro potassium
C) phosphorous(III) chloride
7) The formula of ammonium carbonate is __________.
A) (NH 4 )2CO3 B) NH 4CO2 C) (NH3 )2CO4 D) (NH3 )2CO3
E) N 2 (CO3 )3
8) Chromium and chlorine form an ionic compound whose formula is CrCl3 . The name of this
compound is __________.
A) chromium chlorine
B) chromium(III) chloride
C) monochromium trichloride
D) chromium(III) trichloride E) chromic trichloride
9) Of the following, the smallest and lightest subatomic particle is the __________.
A) neutron
B) proton
C) electron
D) nucleus
E) alpha particle
10) There are __________ electrons, __________ protons, and __________ neutrons in an atom of
132
54 Xe .
A) 132, 132, 54
B) 54, 54, 132
C) 78, 78, 54
D) 54, 54, 78
E) 78, 78, 132
11) Isotopes are atoms that have the same number of _______ but differing number of _______.
A) protons, electrons
B) neutrons, protons
C) protons, neutrons
D) electrons, protons
E) neutrons, electrons
12) The element X has three naturally occurring isotopes. The masses
(amu) and % abundances of the isotopes are given in the table to the
right. The average atomic mass of the element is __________ amu.
A) 219.7
B) 220.4
C) 220.42
D) 218.5
E) 221.0
13) Which pair of elements would you expect to exhibit the greatest similarity in their physical and
chemical properties?
A) O, S
B) C, N C) K, Ca
D) H, He E) Si, P
14) Which of the following compounds would you expect to be ionic?
A) SF6 B) H 2 O C) H 2 O2 D) NH3 E) CaO
15) Which pair of elements is most apt to form a molecular compound with each other?
A) aluminum, oxygen
B) magnesium, iodine
C) sulfur, fluorine
D) potassium, lithium E) barium, bromine
16) Which one of the following compounds is chromium(III) oxide?
A) Cr2O3 B) CrO3 C) Cr3O2 D) Cr3O E) Cr2 O 4
Structure of Atoms
17) The wavelength of light that has a frequency of 1.20 1013 s 1 is __________ m.
A) 25.0
B) 2.50 105 C) 0.0400
D) 12.0
E) 2.5
18) What is the frequency (s1 ) of electromagnetic radiation that has a wavelength of 0.53 m?
A) 5.7  108 B) 1.8 109 C) 1.6  108 D) 1.3 1033 E) 1.3  1033
19) Of the following, __________ radiation has the shortest wavelength.
A) X-ray B) radio
C) microwave
D) ultraviolet
E) infrared
20) The wavelength of a photon that has an energy of 5.25  1019 J is __________ m.
A) 3.79 107 B) 2.64 106 C) 2.38 1023 D) 4.211024 E) 3.79 107
21) The energy of a photon that has a wavelength of 12.3 nm is __________ J.
A) 1.511017 B) 4.42  1023 C) 1.99 1025
D) 2.72  1050
E) 1.62 1017
22) An electron cannot have the quantum numbers n = ______, l = ______, ml = ______.
A) 2, 0, 0
B) 2, 1, -1
C) 3, 1, -1
D) 1, 1, 1
E) 3, 2, 1
23) Which one of the following represents an acceptable set of quantum numbers for an electron in an
atom? (arranged as n, l, ml, and ms)
A) 2, 2, -1, -1/2
B) 1, 0, 0, 1/2
C) 3, 3, 3, 1/2
D) 5, 4,- 5, 1/2
E) 3, 3, 3, -1/2
24) Which one of the following is the correct electron configuration for a ground-state nitrogen atom?
A)
B)
C)
D)
E) None of the above is correct.
25) What is the de Broglie wavelength (m) of a 2.0 kg object moving at a speed of 50 m/s?
A) 6.6  1036 B) 1.5  1035 C) 5.3 1033 D) 2.6  1035
E) 3.8 1034
26) There are __________ orbitals in the third shell.
A) 25
B) 4 C) 9
D) 16
E) 1
27) The azimuthal quantum number is 3 in __________ orbitals.
A) s
B) p C) d
D) f E) a
28) The lowest energy shell that contains f orbitals is the shell with n = __________.
A) 3
B) 2 C) 4
D) 1
E) 5
29) How many quantum numbers are necessary to designate a particular electron in an atom?
A) 3
B) 4 C) 2
D) 1
E) 5
30) There are __________ unpaired electrons in a ground state phosphorus atom.
A) 0
B) 1 C) 2
D) 3
E) 4
31) The ground state electron configuration for Zn is __________.
A) [Kr]4s 2 3d10
B) [Ar]4s 2 3d10 C) [Ar]4s1 3d10
D) [Ar]3s 2 3d10
E) [Kr]3s 2 3d10
32) The largest principal quantum number in the ground state electron configuration of barium is ____.
A) 1
B) 2
C) 4
D) 5
E) 6
33) Which set of three quantum numbers (n, l, ml) corresponds to a 3d orbital?
A) 3, 2, 2
B) 3, 3, 2
C) 3, 2, 3
D) 2, 1, 0
E) 2, 3, 3
34) At maximum, an f-subshell can hold __________ electrons, a d-subshell can hold __________
electrons, and a p-subshell can hold __________ electrons.
A) 14, 10, 6
B) 2, 8, 18
C) 14, 8, 2
D) 2, 12, 21
E) 2, 6, 10
Periodic Properties
35) Elements in the modern version of the periodic table are arranged in order of increasing _______.
A) oxidation number
B) atomic mass
C) average atomic mass
D) atomic number
E) number of isotopes
36) In which set of elements would all members be expected to have very similar chemical properties?
A) O, S, Se B) N, O, F C) Na, Mg, K
D) S, Se, Si
E) Ne, Na, Mg
37) Electrons in the 1s subshell are much closer to the nucleus in Ar than in He due to the larger
__________ in Ar.
A) nuclear charge
B) paramagnetism
C) diamagnetism
D) Hund's rule
E) azimuthal quantum number
38) Of the following, which gives the correct order for atomic radius for Mg, Na, P, Si and Ar?
A) Mg > Na > P > Si > Ar
B) Ar > Si > P > Na > Mg C) Si > P > Ar > Na > Mg
D) Na > Mg > Si > P > Ar
E) Ar > P > Si > Mg > Na
39) The atomic radius of main-group elements generally increases down a group because __________.
A) effective nuclear charge increases down a group
B) effective nuclear charge decreases down a group
C) effective nuclear charge zigzags down a group
D) the principal quantum number of the valence orbitals increases
E) both effective nuclear charge increases down a group and the principal quantum number of the
valence orbitals increases
40) Which one of the following atoms has the largest radius?
A) O
B) F C) S
D) Cl
E) Ne
41) Which one of the following has the smallest radius?
A) Na
B) Cl
C) Fe
D) P
E) Br
42) Which of the following is an isoelectronic series?
A) B5- ,Sr 4- ,As3- ,Te2- B) F ,Cl ,Br  ,I C) S, Cl, Ar, K
D) Si 2- ,P 2- ,S2- ,Cl2-
E) O2- ,F, Ne,Na 
43) Which of the following correctly lists the atoms in order of increasing size (smallest to largest)?
A) F < K < Ge < Br < Rb
B) F < Ge < Br < K < Rb
C) F < K < Br < Ge < Rb
D) F < Br < Ge < K < Rb
E) F < Br < Ge < Rb < K
44) Of the choices below, which gives the order for first ionization energies?
A) Cl > S > Al > Ar > Si
B) Ar > Cl > S > Si > Al
C) Al > Si > S > Cl > Ar
D) Cl > S > Al > Si > Ar E) S > Si > Cl > Al > Ar
45) Of the following elements, which has the largest first ionization energy?
A) Se B) As
C) S
D) Sb
E) Ge
46) Which of the following has the largest second ionization energy?
A) Si
B) Mg C) Al
D) Na E) P
47) Which equation correctly represents the first ionization of aluminum?
A) Al (g)  Al(g)  e B) Al(g)  Al- (g)  e  C) Al(g)  e   Al- (g)
D) Al(g)  Al+ (g)  e-
E) Al (g)  e  Al(g)
48) Which ion below has the largest radius?
A) Cl B) K  C) Br  D) F E) Na 
49) Of the following elements, __________ has the greatest electronegativitiy.
A) Na
B) Li
C) Be
D) N E) F
50) The list that correctly indicates the order of metallic character is __________.
A) B > N > C
B) F > Cl > S
C) Si > P > S
D) P > S > Se
E) Na > K > Rb
Chemical Bonding & Geometry
51) Based on the octet rule, magnesium most likely forms a __________ ion.
A) Mg 2 B) Mg 2 C) Mg 6 D) Mg 6 E) Mg _
52) Based on the octet rule, iodine most likely forms an __________ ion.
A) I2 B) I4 C) I4 D) I  E) I 
53) How many unpaired electrons are there in the Lewis structures of a N 3 ion?
A) 0
B) 1 C) 2
D) 3
E) This cannot be predicted.
54) The halogens, alkali metals, and alkaline earth metals have __________ valence electrons,
respectively.
A) 7, 4, and 6
B) 1, 5, and 7
C) 8, 2, and 3
D) 7, 1, and 2
E) 2, 7, and 4
55) Which of the following would have to lose two electrons in order to achieve a noble gas electron
configuration?
O
Sr
Na
Se
Br
A) O, Se
B) Sr
C) Na D) Br
E) Sr, O, Se
56) 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
57) The Lewis structure of AsH 3 shows __________ nonbonding electron pair(s) on As.
A) 0
B) 1 C) 2
D) 3
E) This cannot be determined from the data given.
58) How many equivalent resonance forms can be drawn for SO 2 without expanding octet on the
sulfur atom (sulfur is the central atom)?
A) 0
B) 2 C) 3
D) 4
E) 1
59) Which of the following does not have eight valence electrons?
A) Ca  B) Rb  C) Xe D) Br  E) All of the above have eight valence electrons.
60) In which of the molecules below is the carbon-carbon distance the shortest?
A) H2C  CH2 B) H-C≡C-H C) H3C  CH3 D) H2C  C  CH 2 E) H3C  CH2  CH3
61) In the Lewis symbol for a sulfur atom, there are __ paired and __ unpaired electrons.
A) 2, 2
B) 4, 2 C) 2, 4
D) 0, 6 E) 5, 1
62) The Lewis structure of the CO 3 2  ion is __________.
A
B
C
D
E
63) Of the following, __________ cannot accommodate more than an octet of electrons.
A) P B) As
C) O
D) S
E) I
64) The central atom in __________ does not violate the octet rule.
A) SF4 B) KrF2 C) CF4 D) XeF4 E) ICl 4 
65) A valid Lewis structure of _______ cannot be drawn without violating the octet rule.
A) NF3 B) BeH 2 C) SO 2 D) CF4 E) SO32 
66) Of the possible bonds between carbon atoms (single, double, and triple), ______.
A) a triple bond is longer than a single bond
B) a double bond is stronger than a triple bond
C) a single bond is stronger than a triple bond
D) a double bond is longer than a triple bond
E) a single bond is stronger than a double bond
67) For a molecule with the formula AB2 the molecular shape is __________.
A) linear or bent B) linear or trigonal planar C) linear or T-shaped D) T-shaped E) trigonal planar
68) The molecular geometry of __________ is square planar.
A) CCl4
B) XeF4
C) PH 3
D) XeF2
E) ICl3
69) The electron domain and molecular geometry of BrO 2  is _________.
A) tetrahedral, trigonal planar
B) trigonal planar, trigonal planar
C) trigonal pyramidal, linear
D) tetrahedral, bent
E) trigonal pyramidal, seesaw
Consider the following species when answering the following questions:
(ii) CCl4 (iii) TeCl4 (iv) XeF4
(i) PCl3
(v) SF6
70) For which of the molecules is the molecular geometry (shape) the same as the VSEPR electron
domain arrangement (electron domain geometry)?
A) (i) and (ii)
B) (i) and (iii)
C) (ii) and (v)
D) (iv) and (v) E) (v) only
71) Of the molecules below, only __________ is nonpolar.
A) CO2 B) H 2 O C) NH3 D) HCl
E) TeCl2
72) Of the molecules below, only __________ is nonpolar.
A) BF3 B) NF3
C) IF3 D) PBr3 E) BrCl3
73) Of the following molecules, only __________ is polar.
A) BeCl2 B) BF3 C) CBr4 D) SiH 2Cl2 E) Cl2
74) Of the following molecules, only __________ is polar.
A) CCl4 B) BCl3 C) NCl3 D) BeCl2 E) Cl2
Mole
75) How many molecules of CH4 are in 48.2 g of this compound?
A) 5.00 1024
B) 3.00
C) 2.90 1025
D) 1.81 10 24
E) 4.00
76) There are __________ atoms of oxygen are in 300 molecules of CH3CO2 H .
A) 300
B) 600
C) 3.011024
D) 3.6110 26
E) 1.80 1026
77) The formula of nitrobenzene is C6 H5 NO2 . The molecular weight of this compound is _____ amu.
A) 107.11
B) 43.03
C) 109.10
D) 123.11
E) 3.06
78) How many grams of oxygen are in 65 g of C2 H 2O2 ?
A) 18
B) 29 C) 9.0
D) 36 E) 130
79) How many moles of carbon dioxide are there in 52.06 g of carbon dioxide?
A) 0.8452
B) 1.183
C) 6.022 1023 D) 8.648 1023 E) 3.134 1025
80) How many atoms of nitrogen are in 10 g of NH 4 NO3 ?
A) 3.5
B) 1.5  10 23
C) 3.0 1023
D) 1.8
E) 2
81) A 22.5-g sample of ammonium carbonate contains __________ mol of ammonium ions.
A) 0.468
B) 0.288
C) 0.234
D) 2.14
E) 3.47
82) The mass % of F in the binary compound KrF2 is __________.
A) 18.48
B) 45.38
C) 68.80
D) 81.52
E) 31.20
83) Calculate the percentage by mass of nitrogen in PtCl2 (NH3 )2 .
A) 4.67
B) 9.34 C) 9.90
D) 4.95
E) 12.67
84) What is the empirical formula of a compound that contains 27.0% S, 13.4% O, and 59.6% Cl by
mass?
A) SOCl
B) SOCl2 C) S2OCl D) SO2Cl E) ClSO4
85) A compound contains 38.7% K, 13.9% N, and 47.4% O by mass. What is the empirical formula of
the compound?
A) KNO3 B) K 2 N2O3 C) KNO2 D) K 2 NO3 E) K 4 NO5
86) Combustion of a 1.031-g sample of a compound containing only carbon, hydrogen, and oxygen
produced 2.265 g of CO2 and 1.236 g of H 2 O . What is the empirical formula of the compound?
A) C3H8O
B) C3H5O
C) C6 H16O2
D) C3H9O3
E) C3H 6O3
87) A compound contains 40.0% C, 6.71% H, and 53.29% O by mass. The molecular weight of the
compound is 60.05 amu. The molecular formula of this compound is __________.
A) C2 H 4O2 B) CH2O C) C2 H3O4 D) C2 H 2O4 E) CHO2
Chemical Reactions
88) When the following equation is balanced, the coefficients are __________.
NH3 (g)  O2 (g)  NO2 (g)  H2O (g)
A) 1, 1, 1, 1
B) 4, 7, 4, 6
C) 2, 3, 2, 3
D) 1, 3, 1, 2
E) 4, 3, 4, 3
89) When the following equation is balanced, the coefficient of H 2S is __________.
A) 1
B) 2
C) 3
FeCl3 (aq)  H2S (g)  Fe2S3 (s)  HCl (aq)
D) 5
E) 4
90) Write the balanced equation for the reaction that occurs when methanol, CH3OH (l) is burned in
air. What is the coefficient of methanol in the balanced equation?
A) 1
B) 2 C) 3
D) 4
E) 3/2
91) Predict the product in the combination reaction below.
Al (s)  N2 (g)  __________
A) AlN
B) Al3 N
C) AlN2
D) Al3 N 2
E) AlN3
92) Of the reactions below, which one is not a combination reaction?
A) C  O2  CO2
B) 2Mg  O2  2MgO
C) 2N 2  3H 2  2NH3
D) CaO  H 2O  Ca(OH) 2 E) 2CH4  4O2  2CO2  4H2O
93) Of the reactions below, which one is a decomposition reaction?
A) NH4Cl  NH3  HCl
B) 2Mg  O2  2MgO
C) 2N 2  3H 2  2NH3
D) 2CH4  4O2  2CO2  4H2O
E) Cd(NO3 )2  Na 2S  CdS  2NaNO3
94) Which one of the following substances is the product of this combination reaction?
Al (s) I2 (s)  
A) AlI 2
B) AlI
D) Al2 I3
C) AlI3
E) Al3I2
95) Which of the following are combination reactions?
1) CH4 (g)  O2 (g)  CO2 (g)  H2O (l)
2) CaO (s)  CO2 (g)  CaCO3 (s)
3) Mg (s)  O2 (g)  MgO (s)
4) PbCO3 (s)  PbO (s)  CO2 (g)
A) 1, 2, and 3
B) 2 and 3
C) 1, 2, 3, and 4
D) 4 only E) 2, 3, and 4
Stoichiometry
96) Lithium and nitrogen react to produce lithium nitride:
6Li (s)  N2 (g)  2Li3 N (s)
How many moles of N 2 are needed to react with 0.500 mol of lithium?
A) 3.00
B) 0.500
C) 0.167
D) 1.50
E) 0.0833
97) The combustion of propane (C3H8 ) produces CO2 and H 2 O :
C3H8 (g)  5O2 (g)  3CO2 (g)  4H2O (g)
The reaction of 2.5 mol of O2 will produce __________ mol of H 2 O .
A) 4.0
B) 3.0 C) 2.5
D) 2.0
E) 1.0
98) Magnesium burns in air with a dazzling brilliance to produce magnesium oxide:
2Mg (s)  O2 (g)  2MgO (s)
When 0.165 mol of magnesium completely burns, the amount of magnesium oxide that is produced is
__________ g.
A) 4.00
B) 6.63 C) 0.165
D) 3.32
E) 13.3
99) The combustion of ammonia in the presence of excess oxygen yields NO 2 and H 2 O :
4 NH3 (g)  7 O2 (g)  4 NO2 (g)  6 H2O (g)
The combustion of 43.9 g of ammonia produces __________ g of NO 2 .
A) 2.58
B) 178 C) 119
D) 0.954
E) 43.9
100) The combustion of ammonia in the presence of excess oxygen yields NO 2 and H 2 O :
4 NH3 (g)  7 O2 (g)  4 NO2 (g)  6 H2O (g)
The combustion of 28.8 g of ammonia consumes __________ g of oxygen.
A) 94.7
B) 54.1 C) 108
D) 15.3
E) 28.8
ANSWERS
Atoms, Molecules, Ions &
Compounds
1) C
2) A
3) D
4) C
5) A
6) B
7) A
8) B
9) C
10) D
11) C
12) B
13) A
14) E
15) C
16) A
Structure of Atoms
17) B
18) A
19) A
20) A
21) E
22) D
23) B
24) D
25) A
26) C
27) D
28) C
29) B
30) D
31) B
32) E
33) A
34) A
73) D
74) C
Periodic Properties
35) D
36) A
37) A
38) D
39) D
40) C
41) B
42) E
43) D
44) B
45) C
46) D
47) D
48) C
49) E
50) C
Chemical Bonding &
Molecular Geometry
51) A
52) E
53) A
54) D
55) B
56) B
57) B
58) B
59) A
60) B
61) B
62) A
63) C
64) C
65) B
66) D
67) A
68) B
69) D
70) C
71) A
72) A
Mole
75) D
76) B
77) D
78) D
79) B
80) B
81) A
82) E
83) B
84) B
85) A
86) A
87) A
Chemical Reactions
88) B
89) C
90) B
91) A
92) E
93) A
94) C
95) B
Stoichiometry
96) E
97) D
98) B
99) C
100) A