Chemistry Chapter 10 The Ho Bond Single Bonde Chlorine Has

General Chemistry, 11e (Petrucci)

Chapter 10 Chemical Bonding I: Basic Concepts

1) A Lewis structure is a combination of Lewis symbols representing either the transfer or the sharing of

electrons in a chemical bond.

2) Covalent bonds are formed by atoms sharing electrons.

3) The core electrons are called valence electrons.

4) A chemical bond for which one of the bonded atoms provides both electrons for the bond is referred to

as a coordinate covalent bond.

5) Polar bonds are caused by the bonding pair of electrons being attracted more to one atom than the

other.

6) Bonds between identical atoms are nonpolar bonds.

7) In a Lewis structure, a terminal atom is bonded to two or more atoms.

8) In a Lewis structure, usually each atom acquires an outer-shell octet of electrons; H has 2 outer shell

electrons.

9) In a Lewis structure, the central atom is typically the atom with the highest electronegativity.

10) In a Lewis structure, the number of valence electrons shown is one less for each negative charge.

11) Valence electrons are:

A) all electrons of the last noble gas configuration

B) electrons in filled orbits

C) electrons in the shell of the highest principal quantum number

D) unpaired electrons

E) paired electrons

12) Choose the INCORRECT statement.

A) The core electrons are called valence electrons.

B) Ionic bonds are formed by the attraction between cations and anions.

C) Ionic bonds are formed from atoms by a transfer of electrons.

D) Covalent bonds are formed by atoms sharing electrons.

E) An octet is 8 outer-shell electrons.

13) Choose the INCORRECT statement.

A) A Lewis symbol consists of a chemical symbol and the outer shell electrons.

B) In a Lewis symbol, the chemical symbol represents the nucleus of the atom.

C) A Lewis structure is a combination of Lewis symbols that represent the transfer or sharing of electrons

in a chemical bond.

D) An ion written as a Lewis symbol has brackets outside the electrons.

E) An ion written as a Lewis symbol has the charge written as a superscript outside the closing bracket.

14) Choose the INCORRECT statement.

A) In a Lewis structure, a covalent bond can be represented by a pair of electrons or a dash.

B) Pairs of electrons not involved in bonding are called lone pairs.

C) A molecule comprised of two atoms is called a diatomic molecule.

D) Two electrons involved in a bond produce a double bond.

E) Three electron pairs involved in a bond produce a triple bond.

15) A chemical bond for which one of the bonded atoms provides both electrons for the bond is referred

to as a:

A) double covalent bond

B) coordinate covalent bond

C) formal covalent bond

D) free radical bond

E) VSEPR bond

16) In which of the following molecules would you expect the nitrogen–to-nitrogen bond to be the

shortest?

A) N2H4

B) N2

C) N2O4

D) N2O

E) NH3

17) Which of the following species contains a triple bond?

A) NH3

B) HCCl3

C) NO3–

D) CO32-

E) CN–

18) Which of the following is least likely to form multiple bonds?

A) phosphorus

B) oxygen

C) nitrogen

D) carbon

E) barium

19) Choose the INCORRECT statement.

A) Bonds between like atoms are nonpolar bonds.

B) Polar bonds are caused by the bonding pair of electrons being attracted more to one atom than the

other.

C) Electronegativity is the ability of an atom to attract electrons when involved in a bond.

D) A difference in electronegativity between two atoms causes a polar bond to be formed.

E) If the difference in electronegativity between two atoms value is large the bond is polar covalent.

20) Which chloride should have the greatest covalent character?

A) NaCl

B) BeCl2

C) KCl

D) BaCl2

E) CaCl2

21) Which of the following exhibits covalent bonding?

A) NaF

B) SrO

C) LiH

D) OF2

E) K2S

22) Which of the following exhibits ionic bonding?

A) C2H6

B) Na2S

C) H2CO

D) SiCl4

E) SF4

23) Which of the following would be properly classified as a set of covalent molecules?

A) NaClO4, C4H10, NH3

B) NaCl, CH4, S8

C) CO2, HCN, O2

D) CO2, NH4Cl, C2H6

E) AgCl, ScF3, P4

24) Which of the following bonds is probably the most polar?

A) N—H in NH3

B) O—H in H2O

C) P—H in PH3

D) Se—H in SeH2

E) C—H in CH4

25) With the representations of “I” for ionic bond, “PC” for polar covalent bond, and “NP” for nonpolar

covalent bond, which of the following descriptive combinations is correct?

A) CsF/PC

B) F2/I

C) NO/NP

D) HCl/PC

E) BrCl/NP

26) Choose the INCORRECT statement.

A) In a Lewis structure, a terminal atom is bonded to two or more atoms.

B) In a Lewis structure all valence electrons must appear.

C) In a Lewis structure, usually all electrons are paired.

D) In a Lewis structure, usually each atom acquires an outer-shell octet of electrons; H has 2 outer shell

electrons.

E) In Lewis structures, most multiple covalent bonds are formed by C, N, O, P, and S.

27) After drawing the Lewis dot structure of HCN, pick the INCORRECT statement from the following.

A) The C-N bond is a double bond.

B) There are no lone pairs on C.

C) The C-H bond is a single bond.

D) There is a lone pair of electrons on N.

E) There are no lone pairs on H.

28) After drawing the Lewis dot structure of HCOOH, pick the INCORRECT statement from the

following.

A) The oxygen not bonded to hydrogen has a double bond to carbon.

B) The carbon has a lone pair.

C) Both oxygens have two lone pairs.

D) The O-H bond is a single bond.

E) The C-H bond is a single bond.

29) After drawing the Lewis dot structure of HOClO2, pick the INCORRECT statement of the following.

A) The oxygen bonded to the hydrogen has two lone pairs.

B) The oxygens not bonded to hydrogen have two lone pairs.

C) The O—Cl bonds are all double bonds.

D) The H—O bond is a single bond.

E) Chlorine has an expanded octet.

30) After drawing the Lewis dot structure of CH2CCl2, pick the INCORRECT statement of the following.

A) The C—C bond is a double bond.

B) The H—C bonds are single bonds.

C) The Cl—C bonds are single bonds.

D) Each carbon has a lone pair.

E) Each chlorine has three lone pairs.

31) As indicated by Lewis structures, which of the following molecules would probably be unstable?

A) NH3

B) N2H6

C) SF4

D) CH2F2

E) SiH4

32) Choose the INCORRECT statement.

A) In a Lewis structure, the number of valence electrons shown is one more for each negative charge.

B) The central atom is typically the atom with the highest electronegativity.

C) One atom supplies both electrons for a coordinate covalent bond.

D) Formal charges are apparent charges associated with atoms in a Lewis structure.

E) Resonance is when more than one plausible structure can be written but the “correct” structure cannot

be written.

33) Which of the following species exhibits resonance?

A) OF2

B) ClO3–

C) N2

D) PCl5

E) BrF3

34) Based on the Lewis structures, which of the following molecules would you expect to exhibit

resonance?

A) LiH

B) CH4

C) HNO2

D) OF2

E) none of these

35) Which of the following species is best represented by a resonance hybrid having two contributing

structures?

A) nitric acid

B) nitrous acid

C) nitride ion

D) nitrate ion

E) nitrogen

36) An expanded octet may occur:

A) in the 1st and 2nd period only

B) in families IA, IIA, and IIIA only

C) anywhere except period 1 and 2

D) in all families except IA

E) in the 3rd and 4th period only

37) Which of the following is diamagnetic?

A) N2

B) O2–

C) SO2+

D) O2

E) NO2

38) Choose the INCORRECT statement.

A) Molecules with all paired electrons are diamagnetic.

B) Highly reactive molecular fragments with unpaired electrons are free radicals.

C) An expanded octet has larger electron clouds.

D) Electron pairs repel each other.

E) VSEPR stands for valence-shell electron pair repulsion.

39) Which of the following is diamagnetic?

A) ClO2

B) NO

C) CO

D) NO2

E) CH3

40) Which of the following must be paramagnetic?

A) F2

B) N2

C) SO2+

D) H2

E) ClO2–

41) Which of the following has a molecular structure best described as involving an “incomplete octet”?

A) OF2

B) BF3

C) CF4

D) NF3

E) F2

42) Which of the following has a molecular structure that can be represented without use of an “expanded

octet”?

A) Fe(CN)63-

B) C2Cl6

C) SF6

D) PF5

E) PtCl5–

43) Which of the following statements correctly describe the basic concepts and uses of VSEPR theory:

I) The VSEPR theory is used for estimating bond angles.

II) The VSEPR theory is used for predicting electronegativities.

III) The VSEPR theory is helpful in predicting polarity.

IV) The VSEPR theory states that electron pairs repel each other.

V) The VSEPR theory uses valence electron counting for structure prediction.

A) I), II), III), IV)

B) I), II), IV), V)

C) I), II), III), V)

D) II), III), IV), V)

E) I), III), IV), V)

44) Choose the correct statement about the compound SO2.

A) The S atom has an unshared electron pair.

B) The S—O bonds are ionic in character.

C) The two S—O bonds have different lengths since one is a single bond and the other a double bond.

D) The molecule has a linear structure.

E) The O atoms have no unshared electron pairs.

45) Which of the following molecules is nonpolar?

A) HCN

B) CHCl3

C) H2O

D) HClO4

E) BCl3

46) Which of the following molecules is polar?

A) NBr3

B) CH4

C) CS2

D) NH4+

E) PCl5

47) Which of the following is a bent (nonlinear) molecule?

A) CO2

B) CS2

C) BeF2

D) OF2

E) XeF2

48) Choose the INCORRECT statement.

A) Molecules with unpaired electrons are paramagnetic.

B) The bond order describes whether a covalent bond is single, double or triple.

C) A larger bond order means a shorter bond length.

D) Polar covalent bonds involve equal sharing of electrons in a bond.

E) Bonds between like atoms share electrons equally.

49) Which of the following species has a trigonal pyramidal structure?

A) ClO3–

B) ClO4–

C) ClO2–

D) ClO2

50) Which of the following sets contains only linear molecules?

A) CO2, HCN, O2

B) H2S, HCN, CO2

C) H2O, CO, Cl2

D) H2S, CO, CO2

E) BF3, Cl2, O2

51) Choose the INCORRECT statement.

A) The geometrical distribution of electron groups is the electron-group geometry.

B) The geometrical arrangement of the atomic nuclei is the molecular geometry.

C) A polar molecule has a dipole moment.

D) A dipole moment is the product of the number of atoms and the charge.

E) A nonpolar molecule can have polar bonds.

52) Choose the groups of molecules below in which all the molecules have a net dipole moment.

A) SiHCl3, O2, H2O

B) HF, H2C=CH2, H2O

C) HF, CH3Cl, H2O

D) CCl4, HCl, NH3

E) HF, H2O, N2

53) Which of the following molecules has both an electron group geometry and a molecular geometry

described as trigonal planar?

A) SiH4

B) PF3

C) OF2

D) CHF3

E) BF3

54) Which of the following molecules contains polar bonds but has a zero dipole moment?

A) N2

B) NH3

C) CO2

D) CH3Cl

E) BrCl

55) Which compound would be expected to have the shortest carbon-carbon bond?

A) H3CCH3

B) HCCH

C) H2CCH2

D) F3CCF3

E) Cl2CCCl2

56) Which compound would be expected to have the shortest nitrogen-nitrogen bond?

A) H2NNH2

B) HNNH

C) N2

D) O2NNO2

E) (CH3)2NNH2

57) Given the bond enthalpies C—C (348), C O (707), O O (498), H—O (464), C—H (414) all in kJ/mol,

compute ΔH° in kJ/mol for the complete combustion of C7H16.

A) -3.13 × 103 kJ/mol

B) -2.93 × 103 kJ/mol

C) -2.57 × 103 kJ/mol

D) -2.43 × 103 kJ/mol

E) +2.57 × 103 kJ/mol

58) How many “dots” should be shown in the Lewis symbol for phosphorus?

A) 1

B) 3

C) 5

D) 8

E) 10