Problem set #6. 1. Which of the following represent the Lewis structure fors?

Transcription

1 Problem set #6 1. Which of the following represent the Lewis structure fors?. Which of the following statements is TRUE? A covalent bond is formed through the transfer of electrons from one atom to another. A pair of electrons involved in a covalent bond are sometimes referred to as "lone pairs." It is not possible for two atoms to share more than electrons. Single bonds are shorter than double bonds. A covalent bond has a lower potential energy than the two separate atoms. 3) Which of the following statements is TRUE? An ionic bond is much stronger than most covalent bonds. An ionic bond is formed through the sharing of electrons. Ionic compounds at room temperature typically conduct electricity. Once dissolved in water, ionic compounds rarely conduct electricity. None of the above are true. 4.Which of the following reactions represent the lattice energy of Li O ( H )? latt + Li O(s) Li (g) O (g) + Li (aq) O (aq) Li O(s) + Li (g) O (g) Li O(s)

2 + Li O(s) Li (aq) O (aq) Li(s) 1 O (g) Li O(s) 5. Which of the following reactions represent the lattice energy of CaS ( H )? latt Ca(s) S(s) CaS(s) CaS(s) Ca(s) S(s) + Ca (aq) S (aq) CaS(s) + Ca (g) S (g) CaS(s) + CaS(s) Ca (aq) S (aq) 6. ) Place the following elements in order of increasing electronegativity. K Cs P P < K < Cs K < P < Cs Cs < P < K Cs < K < P P < Cs < K 7. ) Place the following elements in order of decreasing electronegativity. S Cl Se Se > S > Cl Cl > Se > S Se > Cl > S S > Cl > Se Cl > S > Se 8. Choose the bond below that is least polar. P-F C-Br C-F C-I C-Cl

3 9. Choose the bond below that is most polar. H-I H-Br H-F H-Cl C-H 10. Using periodic trends, place the following bonds in order of increasing ionic character. S-F Se-F O-F Se-F < S-F < O-F S-F < Se-F < O-F O-F < Se-F < S-F Se-F < O-F < S-F O-F < S-F < Se-F 11) Using periodic trends, place the following bonds in order of decreasing ionic character. Sb-Cl P-Cl As-Cl Sb-Cl > As-Cl > P-Cl As-Cl > Sb-Cl > P-Cl Sb-Cl > P-Cl > As-Cl P-Cl > As-Cl > Sb-Cl Sb-Cl > P-Cl > As-Cl 1.Which molecule or compound below contains a pure covalent bond? Li CO 3 SCl 6 Cl PF 3 NaCl 13) Which molecule or compound below contains a polar covalent bond? C H 4 ZnS LiI NCl 3 AgCl 14) Which molecule or compound below contains an ionic bond?

4 CO C Cl 4 SiF 4 OCl NH 4 NO 3 15) Which of the following elements can form compounds with an expanded octet? Se C Li F All of the above elements can form compounds with an expanded octet. 16. How many of the following elements can form compounds with an expanded octet? I O Cl Xe 17. Choose the bond below that is the strongest. C-F C=O C-I I-I C N 18. Choose the best Lewis structure for BeF.

5 19. ) Choose the best Lewis structure for OCl. 0) Choose the best Lewis structure for ICl 5.

6 1) Which of the following elements can form compounds with an expanded octet? N Br F Be None of the above can form compounds with an expanded octet.. Of the following elements, which has the lowest electronegativity? Mg Cl Ca Br 3. The electronegativity is.1 for H and 1.8 for Si. Based on these electronegativities, SiH4 would be expected to be ionic and contain H - ions. be ionic and contain H + ions. have polar covalent bonds with a partial negative charges on the H atoms. have polar covalent bonds with a partial positive charges on the H atoms. 4. The compound ICl contains ionic bonds. nonpolar covalent bonds. polar covalent bonds, with partial negative charges on the Cl atoms. polar covalent bonds, with partial negative charges on the I atoms. 5. The greater the electronegativity difference between two bonded atoms, the greater the bond order. greater the covalent character of the bond. greater the ionic character of the bond. more unstable the bond. 6. How many lone pairs of electrons are on the P atom in PF3? Which one of the following is expected to exhibit resonance?

7 NH4 + HCN CO NO - 8. Two resonance forms for SOCl are given below. Which is favored by the octet rule and which by formal charge considerations? I is favored by the octet rule and by formal charge considerations. I is favored by the octet rule and II by formal charge considerations. II is favored by the octet rule and I by formal charge considerations. II is favored by the octet rule and by formal charge considerations. 9. Assign formal charges to each atom in the resonance form for SOCl given below. 0 for Cl, 0 for S, and 0 for O 0 for Cl, +1 for S, and -1 for O -1 for Cl, +4 for S, and - for O -1 for Cl, - for S, and - for O 30. Which electron dot structure for OCN- has a formal charge of -1 on the most electronegative atom?

8 Problems from Text: 9.1, 9., 9.11,9.9, 9.15, 9.0, 9.7, 9.8, 9.9, 9.30, 9.43, 9.44