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 bond B. Covalent bond C. Coordinate covalent bond D. Metallic bond

2. The shape of the methane molecule (CH4) is called ____. A. linear B. Trigonal planar C. Trigonal pyramidal D. Tetrahedral

C. Hydrogen and halogens D. All diatomic molecules 3. Which elements can form diatomic molecules joined by a single covalent bond? A. Hydrogen only B. Halogens only C. Hydrogen and halogens D. All diatomic molecules

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

A. Covalent B. Ionic C. sigma D. pi 5. A bond that is not symmetrical along the axis between two atomic nuclei is a(n) ____ bond. A. Covalent B. Ionic C. sigma D. pi

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

A. electrons B. protons C. neutrons D. nuclei 7. According to the VSEPR theory, molecules adjust their shapes to keep ____ as far apart as possible. A. electrons B. protons C. neutrons D. nuclei

8. What is the shape of a molecule with the formula AB4? A. Trigonal pyramidal B. tetrahedral C. bent D. Straight line

A. Polar covalent B. Non-polar covalent C. Ionic bond D. Metallic bond 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 covalent C. Ionic bond D. 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. Ar B. Br C. I D. Cl

12. Which of the following covalent bonds is the most polar? A. H-H B. H-O C. N-S D. 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 forces B. Londen dispersion forces C. Van der Waals forces D. All of the above

15. Which of the following concerning carbon tetraiodide is correct? A. Tetrahedral, 109.5, nonpolar B. Tetrahedral, 109.5, polar C. Trigonal pyramidal, 107, nonpolar D. Bent, 104.5, nonpolar

16. What is the shape of a tri-atomic molecule with a triple bond? A. Straight line B. Linear C. Bent D. Tirgonal planar

17. Which of the forces of molecular attraction is the weakest? A. Covalent bond B. Hydrogen bond C. Van der Waals forces D. Dipole-dipole forces

A. Bonding pairs B. Lone pairs C. Single bond D. Pi bond 18. What is the name given to pairs of valence electrons that do not participate in bonding in diatomic oxygen molecules? A. Bonding pairs B. Lone pairs C. Single bond D. Pi bond

19. How many covalent bonds are in a covalently bonded molecule containing 1 phosphorus atom and 3 chlorine atoms? A. 1 B. 2 C. 3 D. 4

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

21. How many unshared pairs of electrons are in a molecule of hydroiodic acid? B. 1 C. 2 D. 3

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

23. What is shape of a molecule of ammonia (NH3)? A. bent B. Trigonal planar C. Trigonal pyramidal D. Tetrahedral

A. 3 sigma B. 1 sigma, 2 pi C. 2 sigma, 1 pi D. 3 pi 24. Which of the following is correct concerning the number of sigma and pi bonds in N2? A. 3 sigma B. 1 sigma, 2 pi C. 2 sigma, 1 pi D. 3 pi

25. What would the bond angle of phosphorus trichloride be? A. 120 B. 109.5 C. 107 D. 104.5

ANSWERS 1. C 9. A 17. C 2. D 10. D 18. B 3. C 11. A 19. C 4. B 12. D 20. D 5. D 13. B 21. D 6. B 14. D 22. B 7. A 15. A 23. C 8. B 16. B 24. B 25. C