Deck 2: Molecules

Question 1

Use the expression for the Coulomb potential energy to calculate the energy for formation of 1 mole of sodium chloride ion-pairs,that is, the energy change for the following reaction:
Na⁺(g)+Cl^-(g) $\rightarrow$ Na⁺Cl^-(g)
Use r₁₂ = 283 pm.

Answer 1

-491 kJ.mol^-1

Question 2

Because of the octet rule,the gaseous O^2- ion is stable.

Answer 2

False

Question 3

All the following elements exist as diatomic gases at room temperature and atmospheric pressure except

A) H.
B) Ar.
C) N.
D) Cl.
E) O.

Answer 3

B

Question 4

An element, E,Has the electronic configuration [Ne] 3s²3p¹.Write the formula of its compound with sulfate.

Question 5

Which of the following has the highest lattice energy?

A) NaCl
B) KI
C) MgO
D) BaO
E) CaO

Question 6

For the ground-state ion I^-1, what type of orbital do the electrons with highest energy reside in?

A) 4d
B) 6s
C) 5p
D) 5d
E) 5s

Question 7

Write the formula of magnesium phosphide.

Question 8

Which of the following has the highest melting point?

A) KF
B) KI
C) RbF
D) KBr
E) KCl

Question 9

If 346 kJ.mol^-1 is released in the reaction Na(g)+ Cl(g) $\rightarrow$ Na⁺Cl^-(g), is the energy change for the reaction Na⁺Cl^-(g) $\rightarrow$ NaCl(s) endothermic or exothermic?

Question 10

For the ground-state ion Pb²⁺, what type of orbital do the electrons with highest energy reside in?

A) 6p
B) 5p
C) 4f
D) 6s
E) 5d

Question 11

Which of the following has the lowest lattice energy?

A) KCl
B) LiCl
C) KBr
D) NaCl
E) KI

Question 12

Use the expression for the Coulomb potential energy to calculate the energy for formation of 1 mole of rubidium chloride ion-pairs, that is,the energy change for the following reaction:
Rb⁺(g)+Cl^-(g) $\rightarrow$ Rb⁺Cl^-(g) Use r₁₂ = 330 pm.

Question 13

How many lone pairs of electrons are found in the Lewis structure of the interhalogen compound ICl₃?

A) 10
B) 4
C) 8
D) 6
E) 7

Question 14

Which of the following metal ions has the ground-state electron configuration [Ar]3d⁶?

A) Ni³⁺
B) Fe²⁺
C) Mn²⁺
D) Cu⁺
E) Ca²⁺

Question 15

For the ground-state ion Bi³⁺, what type of orbital do the electrons with highest energy reside in?

A) 5d
B) 6s
C) 4f
D) 5p
E) 6p

Question 16

For the ground-state ion Sn⁴⁺, what type of orbital do the electrons with highest energy reside in?

A) 4p
B) 5p
C) 4f
D) 4d
E) 5s

Question 17

The Madelung constant is different for all crystals.

Question 18

Metals rarely lose electrons in chemical reactions because

A) their electron affinities are too high.
B) their ionic radii become too small.
C) their ionization energies are too small.
D) their size is too small.
E) their ionization energies are too high.

Question 19

If 491kJ.mol^-1 is released in the reaction Na⁺(g)+Cl^-(g) $\rarr$ Na⁺Cl^-(g), what is the energy change for the reaction Na(g)+ Cl(g) $\rarr$ Na⁺Cl^-(g)? (Hint: See the discussion in the text and apply Hess's Law.)

Question 20

Predict the electronic configuration in the oxide ion in CaO.

A) [He]2s²2p⁶ or [Ne]
B) [He]2s²2p⁵
C) [He]2s²2p⁶3s²
D) [Ne]3s¹3p³
E) [Ne]3s²3p³

Question 21

How many lone pairs of electrons are found in the Lewis structure of hydrazine, H₂NNH₂?

A) 8
B) 4
C) 1
D) 0
E) 2

Question 22

For dinitrogen monoxide, the arrangement of the atoms is N-N-O.In the Lewis structure with a single bond between NN and a triple bond between NO,
The formal charges on N,N,And O,Respectively,Are

A) -1, +1, 0.
B) 0, 0, 0.
C) 0, +1, -1.
D) 0, -1, +1.
E) -2, +1, +1.

Question 23

Which of the following species are radicals?

A) CH₂O
B) HCN
C) HclO
D) ClONO₂
E) ClO

Question 24

Consider the following equilibrium:
S₂O₄^2-(aq) $\Leftrightarrow$ 2SO₂^-(aq)
K ~ 10^-9Write a Lewis structure for each species.

Question 25

Which of the following do not have resonance structures?

A) CH₃CONH^-
B) CH₂COCH₃^-
C) H₂CO
D) All have resonance structures.

Question 26

How many electrons are in the expanded valence in XeO₄?

Question 27

In the most plausible Lewis structure of XeOF₂, there are

A) 2 single bonds, 1 double bond, and 1 lone pair of electrons around Xe.
B) 3 single bonds and 1 lone pair of electrons around Xe.
C) 2 single bonds, 1 double bond, and 3 lone pairs of electrons around Xe.
D) 2 single bonds, 1 double bond, and 2 lone pairs of electrons around Xe.
E) 3 single bonds and 2 lone pairs of electrons around Xe.

Question 28

Draw the "best" Lewis structures of hydrogen azide,HN₁N₂N₃, and the azide ion,N₁N₂N₃^{-S1S1P.The subscripts are used for identification.For each,match the following bond lengths to the correct N-N bond.The bond lengths can be used more than once.
$\begin{array}{lll}&\mathrm{N}-\mathrm{N} \text { bond }&\text { Bond length, pm }\\\text { hydrogen azide } & \mathrm{N}_{1}-\mathrm{N}_{2} & 113 \\& \mathrm{~N}_{2}-\mathrm{N}_{3} & 116 \\\text { azide ion } & \mathrm{N}_{1}-\mathrm{N}_{2} & 124 \\& \mathrm{~N}_{2}-\mathrm{N}_{3} &\end{array}$}

Question 29

Write three Lewis structures for the cyanate ion, NCO^-,Where the arrangement of atoms is N-C-O.In the most plausible structure,

A) there is a triple bond between N and C.
B) there are two double bonds.
C) there is a triple bond between C and O.
D) the formal charge on O is +1.
E) the formal charge on N is -1.

Question 30

Draw the Lewis structure of the formate ion and indicate whether resonance forms are possible.

Question 31

In the "best" Lewis structure of XeO₄,there are two double bonds and the formal charge on Xe is zero.

Question 32

Why are the N-O bond lengths in NO₃^- the same?

Question 33

Draw the Lewis structure of xenon difluoride and give the number of lone pairs electrons around the central atom.

Question 34

How many lone pairs of electrons are found in the Lewis structure of urea, (NH₂)₂CO?

A) 2
B) 3
C) 6
D) 4
E) 8

Question 35

Which of the following species are radicals?

A) CO₂
B) HNO₃
C) NO₂
D) NO^-
E) HNO₃

Question 36

How many electrons are in the expanded valence in XeOF₂?

A) 14
B) 12
C) 8
D) 10
E) 6

Question 37

How many electrons are in the expanded valence in H₂SO₄?

A) 12
B) 14
C) 8
D) 6
E) 10

Question 38

Predict the N-O bond lengths in NO₂^- given the N-O and N=O bond lengths of 140 and 120 pm,respectively.

Question 39

For dinitrogen monoxide, the arrangement of the atoms is N-N-O.In the Lewis structure with a double bond between NN and NO,The formal charges on N,N,And O,Respectively,Are

A) 0, -1, +1.
B) -1, +1, 0.
C) 0, +1, -1.
D) 0, 0, 0.
E) -2, +1, +1.

Question 40

How many electrons are in the expanded valence in I₃^-?

A) 12
B) 6
C) 10
D) 14
E) 8

Question 41

Which of the following species has bonds with the most ionic character?

A) CO₂
B) NO₂
C) SnO₂
D) P₄O₁₀
E) PCl₃

Question 42

Which of the compounds below has bonds with the least covalent character?

A) AgI
B) AgCl
C) AgF
D) AlCl₃
E) BeCl₂

Question 43

Write all possible Lewis structures of sulfur dioxide. Which structure is most feasible?

Question 44

Estimate the CN bond length in urea, NH₂CONH₂.Given: covalent radii (pm)Of C-,77; C=,67; N-,75; N=,60;O-,74; O=,60; H,37.

A) 71 pm
B) 127 pm
C) 76 pm
D) 152 pm
E) 142 pm

Question 45

Which of the following compounds is the least stable?

A) CH₄
B) SnH₄
C) SiH₄
D) GeH₄
E) PbH₄

Question 46

Which of the following species has bonds with the most ionic character?

A) SiO₂
B) PCl₃
C) P₄O₁₀
D) CO₂
E) NO₂

Question 47

Which of the following statements is true?

A) The electronegativity of an atom is defined as electron affinity of the atom.
B) The electronegativity of an atom depends only on the value of the ionization energy of the atom.
C) Atoms with high ionization energies and high electron affinities have low electronegativities.
D) Atoms with low ionization energies and low electron affinities have low electronegativities.
E) Atoms with low ionization energies and low electron affinities have high electronegativities.

Question 48

Use the bond enthalpies given to estimate the heat released when 1-bromobutene, CH₃CH₂CH=CH₂,
Reacts with bromine to give CH₃CH₂CHBrCH₂Br.
Bond enthalpies (kJ.mol^-1): C-H,412; C-C,348; C=C,612; C-Br,276; Br-Br,193.

A) 181 kJ.mol^-1
B) 317 kJ.mo^-1
C) 288 kJ.mol^-1
D) 95 kJ.mol^-1
E) 507 kJ.mol^-1

Question 49

If the following all crystallize in the same type of structure, which has the highest lattice energy?

A) LiCl
B) KF
C) KBr
D) KCl
E) LiF

Question 50

If the following all crystallize in the same type of structure, which has the lowest lattice energy?

A) CaO
B) BaS
C) SrO
D) SrS
E) BaO

Question 51

If the following all crystallize in the same type of structure, which has the highest lattice energy?

A) NaCl
B) NaF
C) KF
D) NaBr
E) NaI

Question 52

Use the bond enthalpies given to estimate the heat released when ethene, CH₂=CH₂,Reacts with HBr to give CH₃CH₂Br.
Bond enthalpies (kJ.mol^-1 ): C-H,412; C-C,348; C=C,612; C-Br,276; Br-Br,193; H-Br,366.

A) 1036 kJ.mol^-1
B) 200 kJ.mol^-1
C) 470 kJ.mol^-1
D) 424 kJ.mol^-1
E) 58 kJ.mol^-1

Question 53

Estimate the CO bond length in acetone, CH₃COCH₃.Given: covalent radii (pm)OfC-,77; C=,67; O-,74;O=,60; H,37.

A) 75.5 pm
B) 127 pm
C) 63.5 pm
D) 151 pm
E) 137 pm

Question 54

Which of the following statements is true?

A) Atoms with high ionization energies and high electron affinities are highly electronegative.
B) Atoms with high ionization energies and high electron affinities have low electronegativities.
C) The electronegativity of an atom depends only on the value of the ionization energy of the atom.
D) Atoms with low ionization energies and low electron affinities have high electronegativities.
E) The electronegativity of an atom is defined as half the electron affinity of the atom.

Question 55

Use the bond enthalpies given to estimate the heat released when 2-methyl-1-propene, (CH₃)₂C=CH₂,
Reacts with HBr to give (CH₃)₂CBrCH₃.Bond enthalpies ( kJ.mol^-1 ):C-H,412; C-C,348;C=C,612; C-Br,276; H-Br,366.

A) 58 kJ.mol^-1
B) 507 kJ.mol^-1
C) 317 kJ.mol^-1
D) 288 kJ.mol^-1
E) 181 kJ.mol^-1

Question 56

Which of the compounds below has bonds with the most covalent character?

A) CaO
B) Li₂O
C) MgO
D) MgS
E) CaS

Question 57

Which of the following compounds contains the strongest bonds to hydrogen?

A) SiH₄
B) CH₄
C) HF
D) H₂S
E) H₂O

Question 58

Use the bond enthalpies given to estimate the heat released when ethene, CH₂=CH₂, Reacts with hydrogen to give CH₃CH₃.Bond enthalpies ( kJ.mol^-1 ): C-H,412; C-C,348; C=C,612; C-Br,276; H-H,436.

A) 124 kJ.mol^-1
B) 342 kJ.mol^-1
C) 288 kJ.mol^-1
D) 148 kJ.mol^-1
E) 560 kJ.mol^-1

Question 59

Which of the compounds below has bonds with the most covalent character?

A) NaCl
B) LiCl
C) CaCl₂
D) BeCl₂
E) MgCl₂

Question 60

Which of the following compounds contains the weakest bonds to hydrogen?

A) CH₄
B) H₂O
C) SiH₄
D) HF
E) H₂S

Question 61

There are three resonance structures of the sulfate ion.A resonance structure can be written where the formal charge on sulfur is 0.

Question 62

The electronegativity of an element can be expressed as ½(I + E_a) where I is the ionization energy and E_a is the electron affinity.

Question 63

Which of the following is a radical?

A) BrO
B) CH₃⁺
C) CH₃^-
D) BF₄^-

Question 64

How many resonance structures can be drawn for N₂O?

A) 0
B) 3
C) 2
D) 1

Question 65

If the following all crystallize in the same type of structure, which has the lowest lattice energy?

A) LiCl
B) NaI
C) NaCl
D) KCl
E) KI

Question 66

Sulfur is more electronegative than oxygen.

Question 67

What is the electronic configuration of Ag?

Question 68

White phosphorus is composed of tetrahedral molecules of P₄ in which each P atom is bonded to three others.In this molecule the formal charge on each P atom is ___.

Question 69

Of the following molecules, which has the strongest bonds?

A) H₂O
B) H₂Se
C) H₂Te
D) H₂S

Question 70

If dinitrogen oxide has a dipole moment,
what is the arrangement of atoms?

Question 71

An element E has the electronic configuration 1s²2s²2p⁴ .What is the formula of its compound with lithium?

A) LiE₂
B) LiE
C) Li₂E
D) Li₄E

Question 72

How many lone pairs of electrons are there in the Lewis structure of Al₂Cl₆?

A) 24
B) 12
C) 4
D) 16

Question 73

The best Lewis structures of SO₂ and O₃ include expanded valence structures such as O=S=O and O=O=O.

Question 74

What is wrong with the following Lewis structure? $$O - C \equiv O$$

A) The valence electron count
B) The positioning of the carbon atom
C) The distribution of valence electrons
D) The charge on the carbon atom
E) The dipole of the molecule

Question 75

White phosphorus is composed of tetrahedral molecules of P₄ in which every P atom is connected to three other P atoms . In the Lewis structure of P₄, There are

A) 3 bonding pairs and 4 lone pairs of electrons.
B) 6 bonding pairs and 2 lone pairs of electrons.
C) 5 bonding pairs and 4 lone pairs of electrons.
D) 6 bonding pairs and no lone pairs of electrons.
E) 6 bonding pairs and 4 lone pairs of electrons.

Question 76

What is the formal charge on the Xe atom in XeF₄?

A) 0
B) -4
C) +2
D) +4

Question 77

Match each of the following compounds with its lattice energy.

Question 78

Which of the following has resonance structures?

A) XeOF₂
B) N₂H₄
C) CH₃CONH^-
D) H₂CO

Question 79

How many valence electrons are present in W⁴⁺?

Question 80

How many double bonds are present in the "best" resonance structure of the phosphate ion?

A) 2
B) 3
C) 1
D) 0