1. Chapter 4 Molecular Geometry and Bonding Theories ExamplesDr.Harbi

2. Valence Shell Electron Pair Repulsion (VSEPR) Theory based on idea that regions of electron density in valence shell of central atom will be distributed in space such that electrostatic repulsions are minimizedbased on idea that regions of electron density in valence shell of central atom will be distributed in space such that electrostatic repulsions are minimized places regions of electron density as far apart as possibleplaces regions of electron density as far apart as possible produces molecular geometryproduces molecular geometry

3. Steps in Predicting Molecular Geometry draw Lewis structure of substancedraw Lewis structure of substance count regions of electron density on central atomcount regions of electron density on central atom draw electron pair shapedraw electron pair shape derive and draw molecular geometryderive and draw molecular geometry

4. Regions of Electron Density single covalent bondsingle covalent bond double covalent bonddouble covalent bond triple covalent bondtriple covalent bond lone pairlone pair unpaired electronunpaired electron

5. # Regions Shape 2linear 180°

6. Shape 2 3 linear trigonal planar 180° 120°

7. # Regions Shape 2 3 linear trigonal planar 4tetrahedral 180° 120° 109.5°

8. 5 trigonal bypyramidal 90° 120°

9. 5 6 octahedral 90° 90° 120°

10. Central Atoms Having Less than an Octet Relatively rare.Relatively rare. Molecules with less than an octet are typical for compounds of Groups 1A, 2A, and 3A.Molecules with less than an octet are typical for compounds of Groups 1A, 2A, and 3A. Most typical example is BF 3.Most typical example is BF 3. Formal charges indicate that the Lewis structure with an incomplete octet is more important than the ones with double bonds.Formal charges indicate that the Lewis structure with an incomplete octet is more important than the ones with double bonds. Exceptions to the Octet Rule

12. Summary of VSEPR Molecular Shapes e-pairsNotationName of VSEPR shapeExamples 2AX 2 LinearHgCl 2, ZnI 2, CS 2, CO 2 3AX 3 Trigonal planarBF 3, GaI 3 AX 2 ENon-linear (Bent)SO 2, SnCl 2 4AX 4 TetrahedralCCl 4, CH 4, BF 4 - AX 3 E(Trigonal) PyramidalNH 3, OH 3 - AX 2 E 2 Non-Linear (Bent)H 2 O, SeCl 2 5AX 5 Trigonal bipyramidalPCl 5, PF 5 AX 4 EDistorted tetrahedral (see-sawed) TeCl 4, SF 4 AX 3 E 2 T-ShapedClF 3, BrF 3 AX 2 E 3 LinearI 3 -, ICl 2 - 6AX 6 OctahedralSF 6, PF 6 - AX 5 ESquare PyramidalIF 5, BrF 5 AX 4 E 2 Square PlanarICl 4 -, BrF 4 -

13. Examples Determine the electron-pair (Domain) and molecular geometries of each of the following. Draw and name each.

14. Beryllium Chloride

15. BeCl 2

16. Beryllium Chloride BeCl 2 1. Lewis structure

17. Beryllium Chloride BeCl 2 1. Lewis structure             Cl Be Cl

18. Beryllium Chloride BeCl 2 1. Lewis structure             Cl Be Cl 2. Count regions of electron density on central atom central atom

19. Beryllium Chloride BeCl 2 1. Lewis structure             Cl Be Cl 2. Count regions of electron density on central atom central atom 2

20. Beryllium Chloride BeCl 2 1. Lewis structure             Cl Be Cl 2. Count regions of electron density on central atom central atom 2 3. Draw and name electron-pair shape             Cl Be Cl linear

21. Beryllium Chloride BeCl 2 3. Draw and name electron-pair shape             Cl Be Cl linear 3. Derive and name molecular shape             Cl Be Cl linear

22. Carbon Dioxide

23. CO 2

24. Carbon Dioxide CO 2         O C O

25. Carbon Dioxide CO 2         O C O 2 regions

26. Carbon Dioxide CO 2         O C O 2 regions Electron-pair shape, linear        O C O

27. Carbon Dioxide CO 2         O C O 2 regions Electron-pair shape, linear        O C O Molecular shape, linear       O C O

28. Aluminum Bromide

29. AlBr 3

30. Aluminum Bromide AlBr 3 Al Br Br Br                  

31. Aluminum Bromide AlBr 3 Al Br Br Br                   3 regions

32. Aluminum Bromide AlBr 3 Al Br Br Br                   3 regions Electron-pair shape trigonal planar Al Br Br Br                  

33. Aluminum Bromide AlBr 3 Al Br Br Br                   3 regions Electron-pair shape trigonal planar Al Br Br Br                   Molecular shape trigonal planar Al Br Br Br                  

34. Nitrite Ion

35. NO 2 –

36. Nitrite Ion NO 2 –       ONO       –

37. Nitrite Ion NO 2 –       ONO       – 3 regions

38. Nitrite Ion NO 2 –       ONO       – 3 regions Electron-pair shape trigonal planar N O O             –

39. Nitrite Ion NO 2 –       ONO       – 3 regions Electron-pair shape trigonal planar N O O             –

40. Nitrite Ion NO 2 –       ONO       – 3 regions Electron-pair shape trigonal planar N O O             – Molecular shape bent bent N O O             –

41. Carbon Tetrabromide

42. CBr 4

43. Carbon Tetrabromide CBr 4 C Br Br Br                   Br      

44. Carbon Tetrabromide CBr 4 C Br Br Br                   Br       4 regions

45. Carbon Tetrabromide CBr 4 C Br Br Br                   Br       4 regions Electron-pair shape tetrahedral C Br Br Br                   Br      

46. Carbon Tetrabromide CBr 4 C Br Br Br                   Br       4 regions Electron-pair shape tetrahedral C Br Br Br                   Br       Molecular shape tetrahedral

47. Arsine

48. Arsine AsH 3

49. Arsine As H H H  

50. Arsine As H H H   4 regions electron-pair shape, tetrahedral

51. Arsine AsH 3 As H H H   4 regions electron-pair shape, tetrahedral As   H H H

52. Arsine AsH 3 As H H H   4 regions electron-pair shape, tetrahedral As   H H H molecular shape trigonal pyramid or tripod

53. Arsine AsH 3 As H H H   4 regions electron-pair shape, tetrahedral As   H H H molecular shape trigonal pyramid or tripod As H H H

54. Water H2OH2OH2OH2O

55. Water H2OH2OH2OH2O O   HH  

56. Water H2OH2OH2OH2O O   HH   4 regions electron-pair shape tetrahedral

57. Water H2OH2OH2OH2O O   HH   4 regions electron-pair shape tetrahedral O   HH  

58. Water H2OH2OH2OH2O O   HH   4 regions electron-pair shape tetrahedral O   HH   molecular shape bent

59. Water H2OH2OH2OH2O O   HH   4 regions electron-pair shape tetrahedral O   HH   molecular shape bent O HH

60. Phosphorus Pentafluoride

61. PF 5                 P F F F F F              

62. Phosphorus Pentafluoride PF 5                 P F F F F F               5 regions electron-pair shape trigonal bipyramidal                 F F F F F               P

63. Phosphorus Pentafluoride PF 5                 P F F F F F               5 regions electron-pair shape trigonal bipyramidal                 F F F F F               P molecular shape trigonal bipyramidal

64. Sulfur Tetrafluoride

65. SF 4

66. Sulfur Tetrafluoride SF 4           S F F F F                

67. Sulfur Tetrafluoride SF 4           S F F F F                 5 regions trigonal bipyramidal

68. Sulfur Tetrafluoride SF 4           S F F F F                 5 regions trigonal bipyramidal                 F F F F           S

69. Sulfur Tetrafluoride SF 4           S F F F F                 5 regions trigonal bipyramidal                 F F F F           S                 F F F F         S molecular shape distorted tetrahedral

70. Sulfur Tetrafluoride SF 4           S F F F F                 5 regions trigonal bipyramidal                 F F F F           S molecular shape see saw S F F F F

71. Chlorine Trifluoride

72. ClF 3

73. Chlorine Trifluoride ClF 3           F F F             Cl

74. Chlorine Trifluoride ClF 3           F F F             Cl 5 regions electron-pair shape trigonal bipyramidal

75. Chlorine Trifluoride ClF 3           F F F             Cl 5 regions electron-pair shape trigonal bipyramidal Cl   F F F                    

76. Chlorine Trifluoride ClF 3           F F F             Cl 5 regions electron-pair shape trigonal bipyramidal Cl   F F F                    

77. Chlorine Trifluoride ClF 3           F F F             Cl 5 regions electron-pair shape trigonal bipyramidal Cl   F F F                     molecular shape T-shape Cl   F F F                

78. Sulfur Hexafluoride

79. SF 6

80. Sulfur Hexafluoride SF 6 S F F F F F F                                    

81. Sulfur Hexafluoride SF 6 S F F F F F F                                     6 regions electron-pair shape octahedral S F F F F F F                                    

82. Sulfur Hexafluoride SF 6 S F F F F F F                                     6 regions electron-pair shape octahedral S F F F F F F                                     molecular shape octahedral

83. Bromine Pentafluoride

84. BrF 5

85. Bromine Pentafluoride BrF 5 Br F F F F F                                

86. Bromine Pentafluoride BrF 5 Br F F F F F                               6 regions electron-pair shape octahedral  

87. Bromine Pentafluoride BrF 5 Br F F F F F                               6 regions electron-pair shape octahedral Br F F F F F                                  

88. Bromine Pentafluoride BrF 5 Br F F F F F                               6 regions electron-pair shape octahedral Br F F F F F                                  

89. Bromine Pentafluoride BrF 5 Br F F F F F                               6 regions electron-pair shape octahedral Br F F F F F                                 molecular shape square pyramidal Br F F F F F                              

90. Xenon Tetrafluoride

91. XeF 4

92. Xenon Tetrafluoride XeF 4 Xe F F F F                            

93. Xenon Tetrafluoride XeF 4 Xe F F F F                             6 regions electron-pair shape octahedral

94. Xenon Tetrafluoride XeF 4 Xe F F F F                             6 regions electron-pair shape octahedral Xe F F F F                            

95. Xenon Tetrafluoride XeF 4 Xe F F F F                             6 regions electron-pair shape octahedral Xe F F F F                           

96. Xenon Tetrafluoride XeF 4 Xe F F F F                             6 regions electron-pair shape octahedral Xe F F F F                            Xe F F F F                         molecular shape square planar

97. Tribromide Ion Br 3 – Br 3 –

98. Tribromide Ion Br 3 – Br 3 – Br                   Br Br

99. Tribromide Ion Br 3 – Br 3 – Br                   Br Br 5 regions electron-pair shape trigonal bipyramidal

100. Tribromide Ion Br 3 – Br 3 – Br                   Br Br 5 regions electron-pair shape trigonal bipyramidal              Br Br      Br

101. Tribromide Ion Br 3 – Br 3 – Br                   Br Br 5 regions electron-pair shape trigonal bipyramidal              Br Br      Br

102. Tribromide Ion Br 3 – Br 3 – Br                   Br Br 5 regions electron-pair shape trigonal bipyramidal              Br Br      Br molecular shape linear             Br Br Br

103. Polarity of Molecules molecules in which dipole moments of the bonds do not cancel are polar moleculesmolecules in which dipole moments of the bonds do not cancel are polar molecules molecules that do not contain polar bonds or in which all dipole moments cancel are non-polar moleculesmolecules that do not contain polar bonds or in which all dipole moments cancel are non-polar molecules

104. CO 2 vs H 2 O C O O O H H

105. C O O O H H  +  –  +  –

106. CO 2 vs H 2 O C O O O H H  +  –  +  –

107. CO 2 vs H 2 O C O O O H H  +  –  +  – 0

108. CO 2 vs H 2 O C O O O H H  +  –  +  – 0

109. CO 2 vs H 2 O C O O O H H  +  –  +  – 0yx yx

110. CO 2 vs H 2 O C O O O H H  +  –  +  – yx y x

111. CO 2 vs H 2 O C O O O H H  +  –  +  – nonpolar polar

112. Study and Know 9.2 Polarity of Molecules

113. VSEPR Theory only explains molecular shapes says nothing about bonding in molecules Enter Valence Bond (VB) Theory atoms share electron pairs by allowing their atomic orbitals to overlap

114. + H H

115. + H H  bond

116. + H H 1s E H

117. + H H 1s E H H

118. + F F F2F2F2F2

119. + F F F2F2F2F2

120. 1s 2s 2p E F

121. 1s 2s 2p F E F

122. Methane CH 4 1s 2s 2p E C

123. Methane 1s 2s 2p E C H H

124. Methane 1s 2s 2p E C H H H+H+H+H+

125. Methane 1s 2s 2p E C H H H+H+H+H+ H–H–H–H–

126. Methane 1s 2s 2p E C H H H+H+H+H+ H–H–H–H– C H H H H 90° 90°

127. Methane C H H H H 109.5° Tetrahedral Geometry 4 Identical Bonds 4 Identical Bonds

128. Problem and Solution C must have 4 identical orbitals in valence shell for bonding solution: hybridization

129. Methane CH 4 1s 2s 2p E

130. Methane 1s 2s 2p E 1s 2s 2p E

131. Methane 1s 2s 2p E 1s 2s 2p E

132. Methane 1s 2s 2p E 1s 2s 2p E

133. Methane 1s 2s 2p E 1s E sp 3

134. – + + + 2p 2s

135. – + + + = 2p 2s an sp 3 hybrid orbital

136. 4 identical sp 3 hybrid orbitals

137. tetrahedral geometry

138. 4 identical sp 3 hybrid orbitals tetrahedral geometry

139. 4 identical sp 3 hybrid orbitals tetrahedral geometry

140. Methane CH 4 1s 2s 2p E 1s E sp 3 H H H H

141. Hybridization vs Shape (e – pair) sp linearsp linear sp 2 trigonal planarsp 2 trigonal planar sp 3 tetrahedralsp 3 tetrahedral sp 3 d trigonal bipyramidalsp 3 d trigonal bipyramidal sp 3 d 2 octahedralsp 3 d 2 octahedral

142. Predict the Hybridization of the Central Atom in tribromide ion in tribromide ion

143. Predict the Hybridization of the Central Atom in tribromide ion in tribromide ion Br 3 –

144. Predict the Hybridization of the Central Atom in tribromide ion in tribromide ion Br 3 – Br                   Br Br 5 regions electron-pair shape trigonal bypyramidal

145. Predict the Hybridization of the Central Atom in tribromide ion in tribromide ion Br 3 – Br                   Br Br 5 regions electron-pair shape trigonal bypyramidal sp 3 d

146. Predict the Hybridization of the Central Atom in carbon dioxide in carbon dioxide CO 2

147. Predict the Hybridization of the Central Atom in carbon dioxide in carbon dioxide CO 2         O C O 2 regions Electron-pair shape, linear

148. Predict the Hybridization of the Central Atom in carbon dioxide in carbon dioxide CO 2         O C O 2 regions Electron-pair shape, linear sp

149. Predict the Hybridization of the Central Atom in aluminum bromide in aluminum bromide

150. Predict the Hybridization of the Central Atom in aluminum bromide in aluminum bromide Al Br Br Br                 3 regions Electron-pair shape trigonal planar  

151. Predict the Hybridization of the Central Atom in aluminum bromide in aluminum bromide Al Br Br Br                 3 regions Electron-pair shape trigonal planar   sp 2

152. Predict the Hybridization of the Central Atom in xenon tetrafluoride in xenon tetrafluoride

153. Predict the Hybridization of the Central Atom in xenon tetrafluoride in xenon tetrafluoride Xe F F F F                             6 regions electron-pair shape octahedral

154. Predict the Hybridization of the Central Atom in xenon tetrafluoride in xenon tetrafluoride Xe F F F F                             6 regions electron-pair shape octahedral sp 3 d 2

155. Consider Ethylene, C 2 H 4

156. C C H H H H

157. C C H H H H 3 regions trigonal planar

158. Consider Ethylene, C 2 H 4 C C H H H H 3 regions trigonal planar sp 2

159. Consider Ethylene, C 2 H 4 C C H H H H 3 regions trigonal planar sp 2

160. 1s 2s 2p E

161. 1s 2s 2p E 1s 2s 2p E

162. 1s 2s 2p E 1s 2p E

163. 2p

164. 2p

167.  bond framework

170.  bond

172. Consider Acetylene, C 2 H 2 C C H H

173. C C H H 2 regions linear

174. Consider Acetylene, C 2 H 2 C C H H 2 regions linear sp

175. Consider Acetylene, C 2 H 2 C C H H 2 regions linear sp

176. 1s 2s 2p E 1s 2s 2p E

177. 1s 2s 2p E 1s sp 2p E

178. sp sp 2p 2p

180.  bond framework

182.  bonds

184. Generally single bond is a  bondsingle bond is a  bond double bond consists of 1  and 1  bonddouble bond consists of 1  and 1  bond triple bond consists of 1  and 2  bondstriple bond consists of 1  and 2  bonds

185. Molecular Orbital (MO) Theory when atoms combine to form molecules, atomic orbitals overlap and are then combined to form molecular orbitals orbitals are conserved a molecular orbital is an orbital associated with more than 1 nucleus like any other orbital, an MO can hold 2 electrons consider hydrogen atoms bonding to form H 2

186. + H H

187. add subtract

188. add subtract bonding antibonding

189. add subtract bonding antibonding  * 1s  1s

190. 1s 1s  * 1s H H H2H2H2H2 E E

191. 1s 1s  1s  * 1s H H H2H2H2H2 E E

192. 1s 1s  1s  * 1s H H H2H2H2H2 E E

193. 1s 1s  1s  * 1s H H H2H2H2H2 E E

194. 1s 1s  1s  * 1s H H H2H2H2H2 E E (  1s ) 2

195. 1s 1s  1s  * 1s H H H2H2H2H2 E E (  1s ) 2 total spin = 0

196. Diamagnetic: slightly repelled by a magnetic fieldDiamagnetic: slightly repelled by a magnetic field total spin = 0 paramagnetic: attracted to a magnetic fielsparamagnetic: attracted to a magnetic fiels total spin not 0 Bond Order = 1/2 (bonding e – – antibonding e – )Bond Order = 1/2 (bonding e – – antibonding e – )

197. 1s 1s  1s  * 1s H H H2H2H2H2 E E (  1s ) 2 total spin = 0 diamagnetic

198. 1s 1s  1s  * 1s H H H2H2H2H2 E E BO = 1/2 ( 2 – 0) = 1

199. Consider He 2

200. 1s 1s  1s  * 1s He He He 2 E E

201. 1s 1s  1s  * 1s He He He 2 E E

202. 1s 1s  1s  * 1s He He He 2 E E (  1s ) 2 (  * 1s ) 2

203. 1s 1s  1s  * 1s He He He 2 E E diamagnetic

204. 1s 1s  1s  * 1s He He He 2 E E BO = 1/2 ( 2 – 2 ) = 0

205. Combination of p Atomic Orbitals

206. 2p 2p

207. subtract add

208. bonding MO antibonding MO subtract add

209. bonding MO antibonding MO  * 2p  2p subtract add

210. 2p 2p

211. subtract add

212. antibonding MO bonding MO subtract add

213.  2p  * 2p subtract add

214.  2p  * 2p subtract add

215. Consider Li 2

216. 2s 2s  2s  * 2s Li Li Li 2 E E 2p  2p  * 2p 2p  2p  * 2p

217. 2s 2s  2s  * 2s Li Li Li 2 E E 2p  2p  * 2p 2p  2p  * 2p

218. 2s 2s  2s  * 2s Be Be Be 2 E E 2p  2p  * 2p 2p  2p  * 2p

219. 2s 2s  2s  * 2s Be Be Be 2 E E 2p  2p  * 2p 2p  2p  * 2p

220. 2s 2s  2s  * 2s B B B2B2B2B2 E E 2p  2p  * 2p 2p  2p  * 2p

221. 2s 2s  2s  * 2s B B B2B2B2B2 E E 2p  2p  * 2p 2p  2p  * 2p

222. 2s 2s  2s  * 2s C C C2C2C2C2 E E 2p  2p  * 2p 2p  2p  * 2p

223. 2s 2s  2s  * 2s N N N2N2N2N2 E E 2p  2p  * 2p 2p  2p  * 2p

224. 2s 2s  2s  * 2s O O O2O2O2O2 E E 2p  2p  * 2p 2p  2p  * 2p

225. 2s 2s  2s  * 2s F F F2F2F2F2 E E 2p  2p  * 2p 2p  2p  * 2p

226. 2s 2s  2s  * 2s Ne Ne Ne 2 E E 2p  2p  * 2p 2p  2p  * 2p