VSEPR

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All of the following are covalent molecules or ions. Draw Lewis dot structures and use VSEPR to predict the shape of each. Use the gumdrops and toothpicks provided to build each chemical species. Be sure that you use one toothpick for each pair of electrons on the central atom. Under each one write the hybridization of the orbitals.

1. CO₂
   • Shape ____________
   • Hybridization ____________
2. BF₄^-
   • Shape ____________
   • Hybridization ____________
3. H₂CO
   • Shape ____________
   • Hybridization ____________
4. PCl₅
   • Shape ____________
   • Hybridization ____________
5. SiH₄
   • Shape ____________
   • Hybridization ____________
6. SeF₆
   • Shape ____________
   • Hybridization ____________
7. IF₄^-
   • Shape ____________
   • Hybridization ____________
8. F₂CO
   • Shape ____________
   • Hybridization ____________
9. XeF₄
   • Shape ____________
   • Hybridization ____________
10. NO₂^-
    • Shape ____________
    • Hybridization ____________
11. O₃
    • Shape ____________
    • Hybridization ____________
12. ClO₃^-
    • Shape ____________
    • Hybridization ____________
13. I₃^-
    • Shape ____________
    • Hybridization ____________
14. IOF₅ (I is the central atom)
    • Shape ____________
    • Hybridization ____________
15. NH₂^-
    • Shape ____________
    • Hybridization ____________

VSEPR (Valence Shell Electron Pair Repulsion)

Regions of electron density	Representative formula	Example	Shape	Hybridization
2	MX2	CO2	Linear (180°)	sp
3	MX3	BF3	Trigonal planar (120°)	sp2
3	MX2E	SO2	Bent (118°)	sp2
4	MX4	CH4	Tetrahedral (109.5°)	cp3
4	MX3E	NH3	Trigonal pyramidal (107°)	sp3
4	MX2E2	H2O	Bent (105°)	sp3
5	MX5	PF5	Trigonal bipyramidal (TBP)	sp3d
5	MX4E	SF4	See Saw	sp3d
5	MX3E2	ICI3	T-shaped	sp3d
5	MX2E3	I3-	Linear	sp3d
6	MX6	SCI6	Octahedral	sp3d2
6	MX5E	XeF5+	Square pyramidal	sp3d2
6	MX4E2	ICI4-	Square planar	sp3d2

Instructors note

Each pair of students needs to be provided with 12 gumdrops (2 of one color and 10 of another), a handful of toothpicks, and a paper napkin or towel to work on.

Answers

1. linear, sp

2. tetrahedral, sp³

3. trigonal planar, sp²

4. trigonal bipyramidal, sp³d

5. tetrahedral, sp³

6. octahedral, sp³d²

7. see saw, sp³d

8. trigonal planar, sp²

9. square planar, sp³d²

10. bent, sp²

11. bent, sp²

12. trigonal pyramidal, sp³

13. linear, sp³d

14. octahedral, sp³d²

15. bent, sp³

Extension: In structure 14, iodine was the central atom. Could oxygen be the central atom? Explain your answer.