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MOLECULAR GEOMETRY VSEPR ACTIVITY. CARBON DIOXIDE Chemical formula: CO 2 # of atoms bonded to central atom: 2 # of lone pairs on central atom: 0 What.

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Presentation on theme: "MOLECULAR GEOMETRY VSEPR ACTIVITY. CARBON DIOXIDE Chemical formula: CO 2 # of atoms bonded to central atom: 2 # of lone pairs on central atom: 0 What."— Presentation transcript:

1 MOLECULAR GEOMETRY VSEPR ACTIVITY

2 CARBON DIOXIDE Chemical formula: CO 2 # of atoms bonded to central atom: 2 # of lone pairs on central atom: 0 What group does the central atom come from? 14 (carbon)

3 CARBON DIOXIDE Draw the Lewis structure: Molecular Geometry Linear Angle: 180

4 WATER Chemical formula: H 2 O # of atoms bonded to central atom: 2 # of lone pairs on central atom: 2 What group does the central atom come from? 16 (oxygen group)

5 WATER Draw the Lewis structure: Molecular Geometry: Bent Angle: 104.5

6 WHY IS THE SHAPE DIFFERENT HERE FOR WATER WHEN COMPARED TO CARBON DIOXIDE? CO 2 Central atom (C): No lone pair electrons. Allows molecule to be “straight” & reduce repulsion between the oxygen’s. H 2 O Central atom (O): 2 lone pairs of electrons. Forces repulsion & distortion.

7 BORON TRIFLUORIDE Chemical formula: BF 3 # of atoms bonded to central atom: 3 # of lone pairs on central atom: 0 What group does the central atom come from? 13 (boron)

8 BORON TRIFLUORIDE Draw the Lewis structure: Molecular Geometry Trigonal Planar Angle: 120

9 AMMONIA Chemical formula: NH 3 # of atoms bonded to central atom: 3 # of lone pairs on central atom: 1 What group does the central atom come from? 15 (nitrogen)

10 AMMONIA Draw the Lewis structure: Molecular geometry: Trigonal pyramidal Bond angle: 107 degrees

11 WHY IS THE ANGLE DIFFERENT HERE FOR AMMONIA WHEN COMPARED TO BORON TRI FLUORIDE? BF 3 Central atom (B): No lone pair electrons. Allows molecule to be “spread out” & reduce repulsion between the fluorine’s. NH 3 Central atom (N): 1 lone pairs of electrons. Forces repulsion & distortion.

12 METHANE Chemical formula: CH 4 # of atoms bonded to central atom: 4 # of lone pairs on central atom: 0 What group does the central atom come from? 14 (carbon)

13 METHANE Draw the Lewis structure: Molecular geometry: tetrahedral Bond angle: degrees

14 WHY IS THE ANGLE FOR METHANE DIFFERENT WHEN COMPARED TO THE ANGLE FOR AMMONIA? NH 3 Central atom (N): 1 lone pairs of electrons. Forces repulsion & distortion. CH 4 Central atom (C): No lone pair electrons. Molecule uses all 4 bond sites giving the distortion.

15 WHAT ARE THE TWO THINGS YOU LOOK FOR TO DETERMINE MOLECULAR SHAPE? Number of ATOMS bonded to the central atom Number of LONE PAIRS on the central atom

16 ARE BONDS IONIC, POLAR COVALENT, OR NON POLAR COVALENT? Example: hydrochloric acid H-Cl H = 2.1 Cl = 3.0 Difference 3.0 – 2.1 = 0.9 Polar covalent

17 USE DELTA VALUES TO DETERMINE IF BONDS BETWEEN TWO ATOMS ARE POLAR COVALENT OR NON POLAR COVALENT Delta values use Lewis structures to predict bond polarity.  area with no electron lone pairs  = area with electron lone pairs left after bonds are formed different:  polar covalent Same:  or  nonpolar covalent

18 FINDING BONDING POLARITY USING DELTA VALUES HCl  Polar covalent CH 4 non polar covalent “C-H”

19 FINDING BONDING POLARITY USING DELTA VALUES Example: hydrochloric acid  Polar covalent


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