Chem 27 Chapter 13

How many electrons are in the Lewis structure for SO2? 18 16 20 32 30

18

How many of the following molecules and ions are linear? NCl3 CH4 SCN- CS2 NO2- 0 1 3 4 2

2

Which of the following molecules does not have a dipole moment? H2Xe None of these has a dipole moment. H2O H2S All of these have a dipole moment.

H2Xe

The molecule XCl5- has a square pyramidal shape. Which of the following atoms could be X? a. O b. S c. P d. at least two of these atoms could be X e. Xe

b. S

Select the correct molecular structure for SO2. none of these bent pyramidal tetrahedral linear

bent

Which statement is correct? a. none of these b. The bonds in LiF have a more covalent character than those in F2 c. H2O is linear d. the diatomic molecule Cl2 is an example of a polar molecule e. the molecule ClO2 cannot be accurately described by a Lewis Structure consistent with the octet rule

e. the molecule ClO2 cannot be accurately described by a Lewis Structure consistent with the octet rule

Which species must be polar? CH4 None of the above CO2 CO C2H4

none of the above

Select the correct molecular structure for SF4. none of these pyramidal linear bent tetrahedral

none of these

Select the correct molecular structure for SF5+. none of these pyramidal square planar octahedral tetrahedral

none of these

Select the correct molecular structure for XeF4. pyramidal linear none of these bent tetrahedral

none of these

Select the correct molecular structure for PF3. tetrahedral octahedral pyramidal square planar none of these

pyramidal

What is the shape of the ICl5 molecule? octahedral none of these trigonal bipyramid see-saw square pyramid

square pyramid

According to the VSEPR model, the electron pairs around NH3 and those around CH4 are arranged differently, because in each case there are a different number of atoms around the central atom. the same, because in each case there are the same number of electron pairs around the central atom. differently or the same, depending on the conditions leading to maximum repulsion. the same, because both nitrogen and carbon are in the second period. differently, because in each case there are a different number of electron pairs around the central atom.

the same, because in each case there are the same number of electron pairs around the central atom.

As indicated by Lewis structures, which of the following would probably not exist as a stable molecule? a. C2H2 b. CH3O c. C3H4 d. CH3OH e. CH2O

b. CH3O

In the gaseous phase, which of the following diatomic molecules would be the most polar? a. NaCl b. CsF c. CsCl d. LiF e. NaF

b. CsF

Which of the following is polar? a. BF3 b. PBr3 c. SBr6 d. KrF2 e. SiF

b. PBr3

Which of the following groups contains no ionic compounds? HCN, NO2, Sr(NO3)2 KH, SrF2, NaNH2 KOH, CBr4, SF4 PCl5, LiBr, Zn(OH)2 CH2O, H2O, NBr3

CH2O, H2O, NBr3

Use the following electronegativity values to answer the question: C 2.5 Cl 3.2 H 2.2 N 3.0 O 3.4 This molecule contains a carbon atom with trigonal planar geometry. CO2 CH3CHO none of these CH3Cl C2H6

CH3CHO

Which ion is planar? SO32- ClO3- CO32- SCl5- PCl4+

CO32-

Choose the molecule with the strongest bond. a. Br2 b. F2 c. I2 d. Cl2

Cl2

Which of the following molecules exhibits the greatest bond energy? Br2 F2 all the same I2 Cl2

Cl2

Calculate the lattice energy for LiF(s) given the following: Sublimation energy for Li(s) +161 kJ/mol ΔHf for F(g) +77 kJ/mol First ionization energy of Li(g) +520. kJ/mol Electron affinity of F(g) -328 kJ/mol Enthalpy of formation of LiF(s) -617 kJ/mol 285 kJ/mol -650. kJ/mol -1047 kJ/mol 800. kJ/mol none of these

-1047 kJ/mol

The distance between the centers of the Li+ and F− ions is 156 pm. Determine the energy of interaction between the pair of ions for a mole of Li+ and F− ions. a. ​−892 kJ/mol b. ​−488 kJ/mol c. ​−973 kJ/mol d. ​−527 kJ/mol e. ​−613 kJ/mol

-892

How many resonance structures does the molecule SO2 have? 4 3 1 2 0

2

How many Lewis structures does CO32- have? 4 3 2 5 1

3

Using the following data reactions: ΔH° (kJ) H2(g) + Cl2(g) → 2HCl(g) -184 H2(g) → 2H(g) 432 Cl2(g) → 2Cl(g) 239 calculate the energy of an H-Cl bond. 428 kJ 326 kJ 518 kJ 770 kJ 856 kJ

428

How many of the following molecules have all of their atoms in the same plane? H2C = CH2 F2O H2CO NH3 CO2 BeCl2 H2O2 5 6 3 7 4

5

Which of the following has the Lewis structure most like that of CO32-? a. NO3- b. SO32- c. O3 d. NO2 e.CO2

a. NO3-

Consider the following molecules. I. BF3 II. CHBr3 (C is the central atom.) III. Br2 IV. XeCl2 V. CO VI. SF4 Select the molecule(s) that fit the given statement. These molecules have a zero net dipole moment. I, III, IV III, V III, IV, V none of them I, III, IV, VI

I, III, IV

Which molecule or ion violates the octet rule? NO3- I3- H2O none of these

I3-

Choose the compound with the most ionic bond. NaCl KF LiCl KCl RbI

KF

As indicated by Lewis structures, which of the following species could probably not exist as a stable molecule? NH3 N2O4 N2H4 N2H2 N2H6

N2H6

Which of the following compounds contains only one unshared pair of valence electrons? NH3 NaCl CH4 H2O BeF3

NH3

What is the electron arrangement around the central atom? Trigonal bipyramid Tetrahedral Pentagonal Octahedral

Octahedral

Which of the following molecules has a dipole moment? none of these SiCl4 Cl2 BCl3 PCl3

PCl3

Which of the following molecules has a nonzero dipole moment? SiH4 PCl3 CBr4 SO3 CO2

PCl3

Which of the following series is isoelectronic? Na, K, Rb, Cs F-, Cl-, K+, Rb+ Sn, As, S, F S2-, Cl-, K+, Ca2+ B, C, N, O

S2-, Cl-, K+, Ca2+

Which of the following molecules has a dipole moment? XeF4 SF4 CF4 All of these have a dipole moment. None

SF4

Which of the following bonds would be the most polar without being considered ionic? C-O O-O N-O Si-O Mg-O

Si-O

Which of the following has the smallest radius? Se2- Sr2+ Br+ Rb+ Kr

Sr2+

A quantum chemistry program indicates that the dipole moment of PH3 is zero. Which statement(s) best explains this result? PH3 violates the octet rule and does not exist. A, B, and C A and C only The electronegativities of P and H are very close in value; therefore, no bond dipoles exist. PH3 is a trigonal planar structure and the bond dipoles cancel.

The electronegativities of P and H are very close in value; therefore, no bond dipoles exist.

In the Lewis structure for elemental nitrogen, there is(are) a triple bond between the nitrogens. three unpaired electrons. a double bond between the nitrogens. a single bond between the nitrogens. none of these

a triple bond between the nitrogens

Based on electronegativities, which of the following would you expect to be most ionic? CaF2 CH4 CO2 N2 CF4

a. CaF2

The first electron affinity value for oxygen is _______ and the second electron affinity value is ________. unfavorable (endothermic), favorable (exothermic) unfavorable (endothermic), unfavorable (endothermic) favorable (exothermic), unfavorable (endothermic) More information is needed. favorable (exothermic), favorable (exothermic)

favorable (exothermic), unfavorable (endothermic)

Draw the Lewis structures of the molecules below, and use them to answer the following questions. I. BH3 II. NO2 III. SF6 IV. O3 V. PCl5 Which of these molecules show resonance? I, II III, V II, IV II, V III, IV

ii, iv

Atoms having greatly differing electronegativities are expected to form polar covalent bonds. nonpolar covalent bonds. ionic bonds. covalent bonds. no bonds

ionic bonds

The _____ is defined as the change in energy that takes place when separated gaseous ions are packed together to form an ionic solid. ​lattice energy band gap energy​ atomic binding energy​ ionization energy​

lattice energy