1. 8.4 DETERMINING MOLECULAR SHAPES

2. THE MODEL WE WILL USE TO DETERMINE MOLECULAR SHAPE IS CALLED _________ (V_____________ S_________ E_____________ P________ R____________________)

3. THE ELECTRON PAIRS AROUND THE ____________ ATOM OF A MOLECULAR COMPOUND REPEL EACH OTHER, AND TRY TO GET ________________________ ___________________________________ THIS DETERMINES THE SHAPE OF THE MOLECULE. Begin the process for the VSEPR model by drawing the Lewis structure of the compound.

4. The structure for BeH 2 is the following: Note: compounds of beryllium are often exceptions to the Octet Rule. Be may have only 4 electrons around it.

5. The pairs of electrons around the central atom are referred to as ___________________________________ How many of these surround Be in BeH 2 ? Think of these as balloons. What shape allows the “balloons” to get as far from each other as possible?

6. Compounds of boron are also often exceptions to the Octet Rule. How many electron clouds are around the central atom in BH 3 ?

7. METHANE GAS (CH 4 )

8. Draw methane. How many electron clouds are there around the central atom in methane?

9. LONE PAIRS OCCUPY A POSITION IN SPACE, SO ANY LONE PAIRS _______________________________ ARE INCLUDED IN THE PAIRS OF ELECTRONS THAT AFFECT THE SHAPE.

10. How many electron clouds are there around the central atom in NH 3 ? Are any of them unshared pairs?

11. How many electron clouds are there around the central atom in H 2 O? Are any unshared pairs?

12. Which one of the molecules below has an unshared pair on the central atom? How do you know?

13. Double or triple bonds on the central atom count as a ____________________________ in molecular geometry

14. SULFUR DIOXIDE SO 2

15. SULFUR DIOXIDE How many electron clouds are there around the central atom in SO 2 ? How many unshared pairs are there?

16. Molecules may have more than one central atom. A central atom is an atom that is _____________________________________ within a compound. When there is more than one central atom in a molecules, you must determine the shape around _____________________________________ Can hydrogen be a central atom?

17. ETHANOL (C 2 H 5 OH) is an example.

18. What are the central atoms in ethanol? What are the shapes?