Unit 7 Review

Molecular Compounds

1. When one atom contributes both bonding electrons in a single covalent bond, the bond is called a(n) ____.

A. Ionic bondB. Covalent bondC. Coordinate covalent bondD. Metallic bond

2. The shape of the methane molecule (CH4) is called ____.

A. linearB. Trigonal planarC. Trigonal pyramidalD. Tetrahedral

3. Which elements can form diatomic molecules joined by a single covalent bond?

A. Hydrogen onlyB. Halogens onlyC. Hydrogen and halogensD. All diatomic molecules

4. Experimental evidence suggests that the H-C-H bond angles in ethene, C2H4, are ____ degrees.

A. 180B. 120C. 109.5D. 107

5. A bond that is not symmetrical along the axis between two atomic nuclei is a(n) ____ bond.

A. Covalent B. IonicC. sigmaD. pi

6. How many electrons can occupy a single molecular orbital?

A. 1B. 2C. 4D. 6

7. According to the VSEPR theory, molecules adjust their shapes to keep ____ as far apart as possible.

A. electronsB. protonsC. neutronsD. nuclei

8. What is the shape of a molecule with the formula AB4?

A. Trigonal pyramidalB. tetrahedralC. bentD. Straight line

9. A bond formed between a silicon atom and an oxygen atom is likely to be a(n) ____ bond.

A. Polar covalent B. Non-polar covalentC. Ionic bondD. Metallic bond

10. Which of the following diatomic molecules is joined by a double covalent bond?

A. H2

B. Cl2

C. N2

D. O2

11. Which of these elements does not exist as a diatomic molecule?

A. ArB. BrC. ID. Cl

12. Which of the following covalent bonds is the most polar?

A. H-HB. H-OC. N-SD. H-F

13. What is thought to cause the disperson forces?

A. The movement of protons.B. The movement of electrons.C. Electron transfer.D. The sharing of electrons.

14. What are the weakest attractions between molecules called?

A. Dispersion forcesB. Londen dispersion forcesC. Van der Waals forcesD. All of the above

15. Which of the following concerning carbon tetraiodide is correct?

A. Tetrahedral, 109.5, nonpolarB. Tetrahedral, 109.5, polarC. Trigonal pyramidal, 107, nonpolarD. Bent, 104.5, nonpolar

16. What is the shape of a tri-atomic molecule with a triple bond?

A. Straight lineB. LinearC. BentD. Tirgonal planar

17. Which of the forces of molecular attraction is the weakest?

A. Covalent bondB. Hydrogen bondC. Van der Waals forcesD. Dipole-dipole forces

18. What is the name given to pairs of valence electrons that do not participate in bonding in diatomic oxygen molecules?

A. Bonding pairsB. Lone pairsC. Single bondD. Pi bond

19. How many covalent bonds are in a covalently bonded molecule containing 1 phosphorus atom and 3 chlorine atoms?

A. 1B. 2C. 3D. 4

20. What is the bond angle in a water molecule?

A. 120B. 109.5C. 107D. 104.5

21. How many unshared pairs of electrons are in a molecule of hydroiodic acid?

A. 0B. 1C. 2D. 3

22. How many sigma bonds are there in a molecule of carbon dioxide?

A. 1B. 2C. 3D. 4

23. What is shape of a molecule of ammonia (NH3)?

A. bentB. Trigonal planarC. Trigonal pyramidalD. Tetrahedral

24. Which of the following is correct concerning the number of sigma and pi bonds in N2?

A. 3 sigmaB. 1 sigma, 2 piC. 2 sigma, 1 piD. 3 pi

25. What would the bond angle of phosphorus trichloride be?

A. 120B. 109.5C. 107D. 104.5

ANSWERS1. C 9. A 17. C2. D 10. D 18. B3. C 11. A 19. C4. B 12. D 20. D5. D 13. B 21. D6. B 14. D 22. B7. A 15. A 23. C8. B 16. B 24. B

25. C