Multiple-Choice

1. Which of these molecules has a shape related to a tetrahedron (or has sp³ bonding)?

(A) CBr₄ and NH₃
(B) PF₅
(C) NH₃ and HCN
(D) SO₃

2. Which of these molecules has the largest bond angle?

(A) HCN
(B) PF₅
(C) NH₃
(D) SO₃

3. The observation that the bond lengths found in the nitrate ion are equal is due to

(A) resonance structures
(B) hybridization of the central atom
(C) the presence of ionic bonds
(D) the existence of lone pairs of electrons

4. Which of these molecules have all atoms lying in the same plane?

(A) CBr₄ and NH₃
(B) PF₅
(C) NH₃ and HCN
(D) SO₃ and HCN

5. Which of the following molecules are paired correctly with their molecular geometry?

(A) PF₅, tetrahedron
(B) XeF₄, square planar
(C) CCl₄, trigonal pyramid
(D) SF₆, square pyramid

6. In which of the following are the elements listed in order of increasing electronegativity?

(A) Ba, Zn, C, Cl
(B) N, O, S, Cl
(C) N, P, As, Sb
(D) K, Ba, Si, Ga

7. The difference in bond angles for SBr₂, PBr₃, and CBr₄ is due to

(A) the dissimilarity in bond polarity between the central atom and bromine
(B) the size of the central atom
(C) the presence of several lone pairs of electrons
(D) the variance in bond length and strength

8. Which of the following is a nonpolar molecule containing polar bonds?

(A) H—C≡C—H
(B) H—H
(C) CH₄
(D) F—Be—F
 

9. Which of the following has the fewest pi bonds and is nonpolar?

(A) HCCH
(B) CO₂
(C) 
(D) N₂

10. The following diagram is an incomplete Lewis structure.

What does the complete Lewis structure for the diagram have?

(A) Both polar and nonpolar bonds
(B) At least one double bond
(C) Resonance forms
(D) At least one lone pair of electrons on each atom

11. Which of the following is NOT a linear structure?

(A) I₂
(B) 
(C) CO₂
(D) H₂S

12. The Lewis structure of the cyanide ion most closely resembles

(A) N₂
(B) O₂
(C) CO₂
(D) NO

13. In which of the following pairs are the two items NOT properly related?

(A) sp³ and 109.5°
(B) Trigonal planar shape and 120°
(C) sp and 180°
(D) Square planar shape and 120°

14. The nitrate ion, , can be described by the following Lewis structures:

What does this diagram mean?

(A) Two nitrogen to oxygen bonds are single bonds and a third is a double bond.
(B) The nitrate ion can exist as three equal forms in equilibrium.
(C) The nitrate ion exists in one form that is an average of all three structures shown.
(D) The electrons are rapidly exchanged among the three forms.

15. Which of the following has a nonbonding pair of electrons on the central atom?

(A) BCl₃
(B) NH₃
(C) CCl₂Br₂
(D) PF₅

16. Which of the following is true when the C=C and C≡C bonds are compared?

(A) The triple bond is shorter than the double bond.
(B) The double bond vibrates at a lower frequency than the triple bond.
(C) The double-bond energy is lower than the triple-bond energy.
(D) All of the above are true.

17. Why does a molecule of BF₃ have no overall dipole moment but a molecule of PF₃ does?

(A) The overall structure of BF₃ is linear.
(B) The atomic radius of phosphorus is larger than the atomic radius of boron.
(C) The overall structure of BF₃ is trigonal planar.
(D) BF₃ does not have a symmetrical structure but PF₃ does.

18. There are ___ sigma bonds and ___ pi bonds in the following compound.

(A) 7, 2
(B) 6, 3
(C) 8, 1
(D) 9, 0

19. The molecular shape (geometry) of a Cl₂CO molecule is ________.

(A) trigonal planer
(B) tetrahedron pyramidal
(C) trigonal pyramidal
(D) bent

20. Sulfur forms the following compounds: SO₂, SCl₂, and . Which form of hybridization is NOT represented by these molecules?

(A) sp
(B) sp²
(C) sp³
(D) None of these

21. Which of the following is least related to the strength of a covalent bond?

(A) vibrational frequency
(B) bond order
(C) bond length
(D) bond direction

Free-Response

Answer the following questions regarding the concepts and properties concerning the structure and geometry of molecular compounds.