21) A chlorine atom in Cl2 should have a

A) charge of 1-.

B) partial charge δ-.

C) partial charge δ+.

D) charge of 0.

22) Element A has an electronegativity of 0.8 and element B has an electronegativity of 3.0. Which statement best describes the bonding in A3B?

A) The AB bond is largely covalent with a δ- on A.

B) The AB bond is largely covalent with a δ+ on A.

C) The compound is largely ionic with A as the cation.

D) The compound is largely ionic with A as the anion.

23) Based on the indicated electronegativities, arrange the following in order of increasing ionic character: CsBr, LaBr3, PBr3, MgBr2.

A) CsBr, LaBr3, MgBr2, PBr3

B) CsBr, MgBr2, PBr3, LaBr3

C) PBr3, LaBr3, MgBr2, CsBr

D) PBr3, MgBr2, LaBr3, CsBr

24) The electronegativities for the elements vary from 0.7 for cesium to 4.0 for fluorine. The electronegativity for iodine is 2.5. Based entirely on the general guidelines for electronegativities and bond character,

A) binary compounds with iodine should all be polar covalent with a δ- on I.

B) binary compounds with iodine should all be polar covalent with a δ+ on I.

C) compounds with iodine may be ionic, polar covalent, or nonpolar covalent.

D) no binary compounds with iodine should be substantially ionic.

25) Arrange the following in order of increasing ionic character: Al2S3, MgS, Na2S, P4S3, S8.

A) MgS, Na2S, Al2S3, P4S3, S8

B) Na2S, MgS, Al2S3, P4S3, S8

C) S8, P4S3, Al2S3, MgS, Na2S

D) S8, P4S3, Al2S3, Na2S, MgS

26) The formula for dinitrogen trioxide is

A) N(OH)3.

B) (NO3)2.

C) N2O3.

D) N3O2.

27) The compound, NO2, is named

A) nitrate.

B) nitrite.

C) nitrogen dioxide.

D) nitrogen(IV) oxide.

28) A::A represents

A) a double bond.

B) a quadruple bond.

C) one lone pair of electrons.

D) two lone pairs of electrons.

29) The nitrogen-nitrogen bond in :NN: has a bond order of

A) 3

B) 1

C) 2

D) 6

30) A coordinate covalent bond may be formed when

A) the central atom donates both electrons in forming a single bond

B) the central atom donates a pair of electrons and the terminal atom donates a pair of electrons to from a double bond.

C) a covalent bond has a bond order of 1.5.

D) a covalent bond has a bond order of 3.