eTrigonal Planar (sp2 hybridization)BF3Use a trigonal planar center (has 3 or 5 prongs depending on the model kit) and three rods of the same color for the three F's to make a model of boron trifluoride. (If you have a model kit without a 3 prong center, use the 5 prong center and put the three Fs on the 3 equivalent positions.)GeometryLewis dot diagram# of s bonds on B# atoms in one planeApproximate F-B-F angleNO31-The BF3 model is the same model needed for the nitrate ion.GeometryLewis dot diagramTotal # of bonds on N_________# of s bonds on N_________# of p bonds on N_________If Px & Py are used for SP2 hybridization what is the function of Pz ?Location of p bond compared to plane of the molecule__________Approximate O-N-O angle________H2C=CH2Use sp2 centers for both C atoms and four rods of the same color for the four H's to make a model of ethene, which has a C=C bond. This is a planar molecule. If your model kit has a 5 prong center, align the 4th and 5th positions on the two C atoms parallel with each other. With a 3 prong center, put a rod through the hole in the center of each and align these rods parallel. These represent the Pz orbital on each C atom which overlap and form the pi?bond between the carbons. In contrast to single bonds (sigma only) which have free rotation, there is no rotation around bonds that contain pi?bonds. You would have to break the pi?bond in order to rotate about such a bond and that requires too much energy for rotation to occur.(Rods through holes in center of 3 prong framework)(With the 3 prong centers, now that you realize there is no rotation about the C=C bond and why, remove the rods through the center holes to make it easier to see the planar nature of the molecule.)GeometryLewis dot diagram# of s bonds on C# of p bonds on C# atoms of ethene in one planeApproximate H-C-H angle Approximate H-C-C angleConsider the H?numbers in the drawing above. Replace H1 and H3 with different color rods to re...
