高中化学 第二章第二节 分子的立体结构教案 新人教版选修3（High school chemistry, second chapters, second sections of the three-dimensional structure of the teaching plan, new teaching edition, elective 3）.doc

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1、高中化学 第二章第二节 分子的立体结构教案 新人教版选修3（High school chemistry, second chapters, second sections of the three-dimensional structure of the teaching plan, new teaching edition, elective 3）Topic: second dimensional structure of molecules (1)ClassClass hourteachlearnorderTheknowledgeandSkill1. recognize the diver

2、sity and complexity of covalent molecules2. a preliminary understanding of valence electron pair repulsion model;3., the three-dimensional structure of simple molecules or ions can be predicted by using the VSEPR model;processandMethodemotionattitudeSense of worthTrain students rigorous and scientif

3、ic attitude and spatial imaginationA keyThe three-dimensional structure of molecules; the valence electron pair repulsion model is used to predict the solid structure of moleculesDifficult pointValence electron pair repulsion theoryknowknowledgejunctionstructureandplatebookset upmeterThe second dime

4、nsional structure of moleculesA variety of molecules1., three atomic molecular structure: linear, C02, CS2, V, such as H2O, S02 and so on.2., four atoms of three-dimensional structure: Flat Triangle: such as formaldehyde (CH20) molecules, such as triangular cone: such as ammonia molecules.3., five a

5、tom molecular structure: positive tetrahedral, such as methane, P4 and so on.4. molecular structure measurement: infrared spectrometer, absorption peak and analysis.Two, valence electron pair repulsion model1. valence electron mutual exclusion model2. VSEPR Theory: molecules or ions of ABn, A atom v

6、alence shell electron pair (including electron for the formation of covalent bonding and not of the lone pair electrons) between the repulsive force, will make the atoms in molecules in the relative position as far as possible, in order to make between the minimum system of the lowest energy molecul

7、ar repulsion.3. valence electron pair repulsion model:(1) valence electrons on the central atom are used to form covalent bonds: the repulsion of valence electrons in molecules(2) the central atom has lone pair electrons: the lone pair electrons also occupy the space around the central atom, and par

8、ticipate in the repulsion of each other so that the spatial structure of molecules changes.The application of 4. valence electron pair repulsion theory(1) determine the number of valence electrons in the central atom A valence layer(2) calculation method of valence electron logarithm(3) determine th

9、e spatial configuration of valence electron pairs(4) determination of molecular space configurationteaching processTeaching steps and contentsTeaching methods, means and activities of teachers and studentsreview the three parameters of the covalent bond.transition we know that many molecules have ce

10、rtain spatial structures, such as:. What is the reason for the difference in the spatial structure of molecules, and what is the relationship between the three parameters of covalent bonds? We began to study the three-dimensional structure of molecules.Second the three-dimensional structure of the m

11、oleculeA variety of molecules most molecules are made up of more than two atoms, so there is the problem of the spatial relation of atoms in molecules, which is called the three-dimensional structure of molecules. For example, the solid structure of three atom molecules has two kinds of linear and V

12、 shapes. If the C02 molecule is linear, and the H20 molecule is V, the bond angle of the two H - O bonds is 105 degrees.projectionblackboard writing1, three atomic molecular structure: linear, C02, CS2, V, such as H2O, S02 and so on.two most four atom molecules adopt plane, triangular and triangular

13、 cones. For example, formaldehyde (CH20) molecules are planar triangles with a bond angle of about 120 degrees;The ammonia molecule assumes a triangular cone with a bond angle of 107 degrees.projectionblackboard writing2, four atomic molecular structure: Flat Triangle: such as formaldehyde (CH20) mo

14、lecules, such as triangular cone: such as ammonia molecules.28 the more solid structure of the five atom molecule, the most common is the tetrahedral structure, such as the three-dimensional structure of methane molecules, is a four body shape, the bond angle is 109 degrees.projectionblackboard writ

15、ing3, five atomic molecular structure: four sides of the body, such as methane, P4 and so on.The world of molecules is so varied, so colorful and so beautiful that it is so fascinating that the solid structure of the molecule is related to its stability. For example, the S8 molecule, such as a crown

16、 crown, would be less stable than the crown if one of the upward sulfur atoms turned upside down; and, for example, the chair C6H12 would be more stable than the boat type.projectionquestion the molecular space structure we see, then how scientists measured?projectionreading scientific perspective - how is the three-dimensional structure of molecules measured?The naked eye can not see the molecules, then, how scientists know the molecular shape? Early scientists rely mainly on the macroscopic properties of the material obtained after the system summary that now, scientists