Chapter 8 2 Elements from opposite sides of the periodic table tend

21) The formula of palladium(IV) sulfide is __________.

A) Pd2S4

B) PdS4

C) Pd4S

D) PdS2

E) Pd2S2

22) 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

23) Determining lattice energy from Born-Haber cycle data requires the use of __________.

A) the octet rule

B) Coulomb’s law

C) Periodic law

D) Hess’s law

E) Avogadro’s number

24) A __________ covalent bond between the same two atoms is the longest.

A) single

B) double

C) triple

D) They are all the same length.

E) strong

25) How many hydrogen atoms must bond to silicon to give it an octet of valence electrons?

A) 1

B) 2

C) 3

D) 4

E) 5

26) A double bond consists of __________ pairs of electrons shared between two atoms.

A) 1

B) 2

C) 3

D) 4

E) 6

27) A triple bond consists of __________ pairs of electrons shared between two atoms.

A) 1

B) 2

C) 3

D) 4

E) 6

28) What is the maximum number of double bonds that a hydrogen atom can form?

A) 0

B) 1

C) 2

D) 3

E) 4

29) What is the maximum number of double bonds that a carbon atom can form?

A) 4

B) 1

C) 0

D) 2

E) 3

30) What is the maximum number of triple bonds that a carbon atom can form?

A) 4

B) 1

C) 0

D) 2

E) 3

31) In the molecule below, which atom has the largest partial negative charge?

Cl

∣

F C Br

∣

I

A) Cl

B) F

C) Br

D) I

E) C

32) The ability of an atom in a molecule to attract electrons is best quantified by the __________.

A) paramagnetism

B) diamagnetism

C) electronegativity

D) electron change-to-mass ratio

E) first ionization potential

33) Given the electronegativities below, which covalent single bond is most polar?

Element: H C N O

Electronegativity: 2.1 2.5 3.0 3.5

A) C H

B) N H

C) O H

D) O C

E) O N

34) Electronegativity __________ from left to right within a period and __________ from top to bottom

within a group.

A) decreases, increases

B) increases, increases

C) increases, decreases

D) stays the same, increases

E) increases, stays the same

35) Electropositivity __________ from left to right within a period and __________ from top to bottom

within a group.

A) decreases, increases

B) increases, increases

C) increases, decreases

D) stays the same, increases

E) increases, stays the same

36) A nonpolar bond will form between two __________ atoms of __________ electronegativity.

A) different, opposite

B) identical, different

C) different, different

D) similar, different

E) identical, equal

37) The ion ICI4– has __________ valence electrons.

A) 34

B) 35

C) 36

D) 28

E) 8

38) The ion NO– has __________ valence electrons.

A) 15

B) 14

C) 16

D) 10

E) 12

39) The ion PO43- has __________ valence electrons.

A) 14

B) 24

C) 27

D) 29

E) 32

40) The Lewis structure of AsH3 shows __________ nonbonding electron pair(s) on As.

A) 0

B) 1

C) 2

D) 3

E) This cannot be determined from the data given.

41) The Lewis structure of PF3 shows that the central phosphorus atom has __________ nonbonding

and __________ bonding electron pairs.

A) 2, 2

B) 1, 3

C) 3, 1

D) 1, 2

E) 3, 3

42) The Lewis structure of HCN (H bonded to C) shows that __________ has __________ nonbonding

electron pairs.

A) C, 1

B) N, 1

C) H, 1

D) N, 2

E) C, 2

43) The formal charge on carbon in the molecule below is __________.

A) 0

B) +1

C) +2

D) +3

E) -1

44) The formal charge on nitrogen in NO3– is __________.

A) -1

B) 0

C) +1

D) +2

E) -2

45) The formal charge on sulfur in SO42- is __________, where the Lewis structure of the ion is:

A) -2

B) 0

C) +2

D) +4

E) -4

46) In the Lewis structure of ClF, the formal charge on Cl is __________ and the formal charge on F is

__________.

A) -1, -1

B) 0, 0

C) 0, -1

D) +1, -1

E) -1, +1

47) In the Lewis structure of HCO3–, the formal charge on H is __________ and the formal charge on C

is __________.

A) -1, -1

B) 0, 0

C) 0, -1

D) +1, -1

E) -1, +1

48) In the resonance form of ozone shown below, the formal charge on the central oxygen atom is

__________.

A) 0

B) +1

C) -1

D) +2

E) -2

49) How many equivalent resonance forms can be drawn for CO32-(carbon is the central atom)?

A) 1

B) 2

C) 3

D) 4

E) 0

50) How many equivalent resonance forms can be drawn for SO2 without expanding octet on the sulfur

atom (sulfur is the central atom)?

A) 0

B) 2

C) 3

D) 4

E) 1

51) How many equivalent resonance structures can be drawn for the molecule of SO3 without having to

violate the octet rule on the sulfur atom?

A) 5

B) 2

C) 1

D) 4

E) 3

52) How many different types of resonance structures can be drawn for the ion SO32- where all atoms

satisfy the octet rule?

A) 1

B) 2

C) 3

D) 4

E) 5

53) Using the table of average bond energies below, the ΔH for the reaction is __________ kJ.

Bond: C≡C C–C H–I C–I C–H

D (kJ/mol): 839 348 299 240 413

A) +160

B) -160

C) -217

D) -63

E) +63

54) Using the table of average bond energies below, the ΔH for the reaction is __________ kJ.

H–C≡C–H (g) + H–I (g) → H2CCHI (g)

Bond: C≡C C=C H–I C–I C–H

D (kJ/mol): 839 614 299 240 413

A) +506

B) -931

C) -506

D) -129

E) +129

55) Using the table of average bond energies below, the △H for the reaction is __________ kJ.

C≡O (g) + 2H2 (g) → H3C–O–H (g)

Bond: C–O C=O C≡O C–H H–H O–H

D (kJ/mol): 358 799 1072 413 436 463

A) +276

B) -276

C) +735

D) -735

E) -116

56) Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is

__________ kJ.

A) -44

B) 38

C) 304

D) 2134

E) -38

57) Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is

__________ kJ.

A) 291

B) 2017

C) -57

D) -356

E) -291

58) Using the table of bond dissociation energies, the ΔH for the following reaction is __________ kJ.

2HCl (g) + F2 (g) → 2HF (g) + Cl2 (g)

A) -359

B) -223

C) 359

D) 223

E) 208

8.3 Algorithmic Questions

1) There are __________ paired and __________ unpaired electrons in the Lewis symbol for a chlorine

atom.

A) 4, 2

B) 4, 1

C) 6, 1

D) 0, 5

E) 2, 5

2) There are __________ unpaired electrons in the Lewis symbol for a (an) sodium ion.

A) 3

B) 2

C) 0

D) 4

E) 1

3) The principal quantum number of the electrons that are lost when tungsten forms a cation is

__________.

A) 6

B) 5

C) 4

D) 3

E) 2

4) The chloride of which of the following metals should have the greatest lattice energy?

A) potassium

B) rubidium

C) sodium

D) lithium

E) cesium

5) How many single covalent bonds must a chlorine atom form to have a complete octet in its valence

shell?

A) 0

B) 1

C) 2

D) 3

E) 4

6) Of the atoms below, __________ is the most electropositive.

A) Be

B) Mg

C) Ca

D) Sr

E) Ba

7) Of the atoms below, __________ is the least electronegative.

A) Ba

B) Be

C) Mg

D) Sr

E) Ca

8) Of the bonds below, __________ is the least polar.

A) C, O

B) N, O

C) C, F

D) S, O

E) K, Br

9) Which two bonds are least similar in polarity?

A) Al-Cl and I-Br

B) O-F and Cl-F

C) B-F and Cl-F

D) I-Br and Si-Cl

E) C-Cl and Ge-Cl

10) Of the following, __________ cannot accommodate more than an octet of electrons.

A) Ni

B) As

C) C

D) V

E) Y

8.4 Short Answer Questions

1) The electron configuration that corresponds to the Lewis symbol, : . is __________.

2) Write the balanced chemical equation for the reaction for which ΔH˚rxn is the lattice energy for

potassium bromide.

3) Using the noble gas shorthand notation, write the electron configuration for Fe+3.

4) Give the electron configuration of Cu2+.

5) Which halogen, bromine or iodine, will form the more polar bond with phosphorus?

6) Draw the Lewis structure of ICl2+.

7) Alternative but equivalent Lewis structures are called __________.

8) Benzene is an __________ compound with __________ equivalent Lewis structures.

9) In a reaction, if the bonds in the reactants are stronger than the bonds in the product, the reaction is

__________.

10) In compounds of __________ and __________, the octet rule is violated due to the presence of

fewer than eight valence electrons.

11) Polyatomic ions with an odd number of electrons will __________ the octet rule.

12) The strength of a covalent bond is measured by its __________.

13) To produce maximum heat, an explosive compound should have __________ chemical bonds and

decompose to molecule with __________ bonds.

14) Calculate the bond energy of C F given that the heat of atomization of CHFClBr is 1502 kJ/mol,

and that the bond energies of C H, C Br, and C Cl are 413, 276, and 328 kJ/mol, respectively.

15) The reaction below is used to produce methanol:

CO (g) + 2H2 (g) → CH3OH (l) ΔHrxn = -128 kJ

(a) Calculate the C H bond energy given the following data:

(b) The tabulated value of the (C-H) bond energy is 413 kJ/mol. Explain why there is a difference

between the number you have calculated in (a) and the tabulated value.

16) From the information given below, calculate the heat of combustion of methane(CH4)(in kJ/mol)

Start by writing the balanced equation.

8.5 True/False Questions

1) Atoms surrounded by eight valence electrons tend to lose electrons.

2) The greater the lattice energy, the greater the charges on the participatory ions and the smaller their

radii.

3) Most transition metals do not form ions with a noble gas configuration.

4) When a metal gains an electron, the process is endothermic.

5) Electron affinity is a measure of how strongly an atom can attract additional electrons.

6) As electronegativity difference increases, bond length will decrease.

7) In some molecules and polyatomic ions, the sum of the valence electrons is odd and as a result the

octet rule fails.

8) Bond enthalpy can be positive or negative.