1. 1 Shapes of Molecules Determined by number of valence electrons of the central atom 3-D shape a result of bonded pairs and lone pairs of electrons Use VSEPR theory (valence-shell-electron-pair repulsion

2. 2 Using the VSEPR Model 1. Draw the electron-dot structure 2.Identify the central atom 3.Count the total number of electron pairs around central atom 4.Predict the electron shape 5.Predict the shape of the molecule using the bonding atoms

3. 3 Shapes of Molecules Number of electron pairs2 (= negative charge clouds) Number of bonded atoms 2 Angle180° Name of shape linear

4. 4 BeCl 2 Be 2 valence electrons.... : Cl : Be : Cl :.... : Cl Be Cl : linear, 180°....

5. 5 More Electron Pairs Electron AngleBonded Name of PairsAtomsShape 3120° 3trigonal planar 3120° 2angular

6. 6 Electron Shape with 3 Pairs

7. 7 BF 3 B has 3 valence electrons 120° Ftrigonal planar B F

8. 8 SO 2 S has 2 bonded atoms, 1 lone pair (electron cloud) 120°, angular...... : O :: S : O : S.. O

9. 9 More Electron Pairs Electron AngleBonded Name of PairsAtomsShape 4109° 4tetrahedral 4109° 3pyramidal 4109° 2bent, angular

10. 10 Tetrahedral CH 4 4 electron Pairs, 4 bonded atoms, 109° H H C H C H H H H H

11. 11 NH 3 Pyramidal N has 4 electron pairs, 3 bonded H atoms Shape is called pyramidal.. H : N : H N.. HH H H..

12. 12 H 2 O Bent or Angular O has 4 electron pairs, 2 bonded H atoms Shape is called bent or angular, 109°.. : O : H O.. H H H..

13. 13 Learning Check Determine the molecular geometry of each of the following: A. CCl 4 1) tetrahedral 2) pyramidal3) angular B. SO 3 1) trigonal planar 2) pyramidal3) angular C. PCl 3 1) trigonal planar 2) pyramidal3) angular

14. 14 Solution Determine the molecular geometry of each of the following: A. CCl 4 1) tetrahedral B. SO 3 1) trigonal planar C. PCl 3 2) pyramidal