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Molecular Structures

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Molecular Structures

- Draw the Lewis dot structure for the molecule
- Use gumdrops, marshmallows, and toothpicks to build a 3D representation of the molecule
- Gumdrop=atom
- Toothpick=bond
- Small marshmallow=shared electron pair
- Large marshmallow=lone electron pair

- Draw a sketch on sheet of your molecule (remember a key!)

- What do you notice about methane?
- How many shared electron pairs are surrounding the central carbon?
- Enter number into Quizdom Remote

- How many shared electron pairs are surrounding the central carbon?

- What do you notice about methane?
- Can it bond with anything else?
- Yes
- No

- Can it bond with anything else?

- 3D Model: Jmol perspective
- Bond Angle: 109.5°

- Molecular Shape Name:
- Tetrahedral
- 4 pairs. All Shared.

- Draw the Lewis dot structure for the molecule
- Use gumdrops, marshmallows, and toothpicks to build a 3D representation of the molecule
- Gumdrop=atom
- Toothpick=bond
- Small marshmallow=shared electron pair
- Large marshmallow=lone electron pair

- Draw a sketch on sheet of your molecule (remember a key!)

- How many shared pairs of electrons are there?

- How many shared pairs of electrons are there?
- Predict what you think will happen to the bond angles between the hydrogens in ammonia compared to the hydrogens in methane:
- A) The angle will increase
- B) The angle will decrease
- C) The angle will remain the same

- 3D Model: Jmol perspective
- With lone pairs
- Bond Angle: 107.6°

- Molecular Shape Name:
- Trigonalpyramidal
- 4 pairs: 3 shared. 1 lone pair

- How many unshared pairs of electrons exist around the central atom?

- 3D Model: Jmol perspective
- Bond Angle: 120°

- Molecular Shape Name:
- Trigonalplanar
- 3 pairs: 3 shared. 0 lone pair

- Which is NOT true about the relationship between water and ammonia?
- A) The bond angle is greater for water than it is for ammonia
- B) The bond angle is smaller for water than it is for ammonia
- C) There are more lone pairs in water
- D) There are fewer shared pairs in water

- 3D Model: Jmol perspective
- With Lone Pairs
- Bond Angle: 104.5°

- Molecular Shape Name:
- Bent
- 4 pairs: 2 shared. 2 lone pair

- How many lone pairs are there?

- How many lone pairs are there?
- How many covalent bonds are formed around the carbon?

- 3D Model: Jmol perspective
- Bond Angle: 180°

- Molecular Shape Name:
- Linear
- 4 pairs: 4 shared. 0lone pair

- How many shared pairs are there?

- How many shared pairs are there?
- How many lone pairs are there around the central atom?

- How many lone pairs are there?

- How many lone pairs are there?
- What would the bond angle be?

- How many lone pairs are there?

- How many lone pairs are there?
- The bond angle for PH3is ______ compared to CH4.
- A) Larger
- B) Smaller
- C) The same

- How many shared pairs around central atom?

- How many shared pairs around central atom?
- How many lone pairs?

- How many shared pairs around central atom?
- How many lone pairs?
- What would you predict the bond angle would be?

- TrigonalBipyramidal
- Jmol representation
- Bond Angles: 90° and 120°
- 5 Total Pairs: 5 Shared pairs 0 Lone Pairs

- Octahedral : SF6
- Jmol Representation
- Bond Angles: 90°
- 6 Total Pairs: 6 shared, 0 Lone Pairs

What do you think would happen if you removed an Fluorine from the central Sulfur atom?

What if you removed another?

How do you think this would affect the molecular model?

The molecular structure is based on electrons (Shared or unshared) arranging themselves so that they have the greatest distance between one another around the central atom.

The goal is to minimize the repulsion between the negatively-charged electrons.