+ Bonding Part III Unit 5: Bonding Mrs. Callender VS E P R

+ Lesson Essential Question: How do I Predict Molecular Shape?

+ VSEPR stands for…. Valence Shell Electron Pair Repulsion The structure around a given atom is determined principally by minimizing electron pair repulsions.

+ How to predict a VSEPR Structure? 1. Draw a Lewis Dot Structure 2. Put pairs as far apart as possible. 3.Determine position of atoms from the way the electron pairs are shared and unshared. 4. Determine the name of the molecular structure from positions of the atoms and electron pairs.

+ Electron Pair Count and Geometry Linear – two pairs on the central atom. Trigonal – three pairs on the central atom. Tetrahedral – four pairs on the central atom.

+ How do I figure out the geometry? Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 2 Linear, 180 o 2 BP Linear BeCl 2 Be– 2 valence e- 2 Cl – 14 valence e- Total = 16 valence e- Cl Be Cl Two Bonding Pair (BP) of electrons and no unbonded pair of electrons fits the Linear criteria. AB 2 E 0

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 3 Trigonal Planar, 120 o 3 BP Trigonal Planar BF 3 B– 3 valence e- 3 F – 21 valence e- Total = 24 valence e- F B F F Three Bonding Pair (BP) of electrons and no unbonded pair of electrons fits the Trigonal Planar criteria. AB 3 E 0

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 3 Trigonal Planar, 120 o 2 BP 1 LP Bent SO 2 S – 6 valence e- 2 O– 12 valence e- Total = 18 valence e- O SO This structure has resonance so the bonds between the S and O represent 2 Bonding Pairs (BP) of electrons. One Lone Pair (LP) of electrons. AB 2 E 1

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 4 Tetrahedral o 4 BP Tetrahedral CH 4 C – 4 valence e- 4 H– 4 valence e- Total = 8 valence e- H C H H H 4 Bonding Pairs of electrons and no Lone Pair of electrons has this compound as a Tetrahedral. AB 4 E 0

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 4 Tetrahedral o 3 BP 1 LP Trigonal Pyramidal NH 3 N – 5 valence e- 3 H– 3 valence e- Total = 8 valence e- H N H H 3 Bonding Pairs of electrons and one Lone Pair of electrons has this compound as a Trigonal Pyramidal. AX 3 E 1

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 4 Tetrahedral o 2 BP 2 LP Bent H2OH2O 2 H – 2 valence e- O– 6 valence e- Total = 8 valence e- H O H 3 Bonding Pairs of electrons and Two Lone Pair of electrons has this compound as a Trigonal Pyramidal. AB 2 E 2

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 5 Trigonal Bipyramidal 120 o, 90 o 5 BP Trigonal Bipyramidal PCl 5 P – 5 valence e- 5 Cl – 35 valence e- Total = 40 valence e- Cl P v v 5 Bonding Pairs of electrons and no Lone Pair of electrons has this compound as a Trigonal Bipyramidal Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. AX 5 E 0

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 5 Trigonal Bipyramidal 120 o, 90 o 4 BP 1 LP See-Saw SF 4 S – 6 valence e- 4 F – 28 valence e- Total = 34 valence e- F S F F F v v 4 Bonding Pairs of electrons and One Lone Pair of electrons has this compound as a See Saw Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. AX 4 E 1

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 5 Trigonal Bipyramidal 120 o, 90 o 3 BP 2 LP T-Shaped ICl 3 I – 7 valence e- 3 Cl – 21 valence e- Total = 28 valence e- Cl I 3 Bonding Pairs of electrons and Two Lone Pair of electrons has this compound as T-Shaped. Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. AX 3 E 2

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 5 Trigonal Bipyramidal 120 o, 90 o 2 BP 3 LP Linear I I – 21 valence e- -1 charge – 1 valence e- Total = 22 valence e- I I I 2 Bonding Pairs of electrons and Three Lone Pair of electrons has this compound as Linear. Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. AX 2 E 3

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 6 Octahedral 90 o 6 BP Octahedral SF 6 S – 6 valence e- 6 F – 42 valence e- Total = 48 valence e- Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. F S F F F F F 6 Bonding Pairs of electrons and no Lone Pair of electrons has this compound as an Octahedral. AX 6 E 0

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 6 Octahedral 90 o 5 BP 1 LP Square Pyramid IF 5 I – 7 valence e- 5 F – 35 valence e- Total = 42 valence e- Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. F I F F F F 5 Bonding Pairs of electrons and One Lone Pair of electrons has this compound as a Square Pyramidal. AX 5 E 1

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 6 Octahedral 90 o 4 BP 2 LP Square Planar XeF 4 Xe – 8 valence e- 4 F – 28 valence e- Total = 32 valence e- Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. F Xe F F F 4 Bonding Pairs of electrons and Two Lone Pair of electrons has this compound as a Square Planar AX 4 E 2

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 7 Pentagonal Bipyramid 7 BP Pentagonal Bipyramid IF 7 I – 7 valence e- 7 F – 49 valence e- Total = 56 valence e- Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. AX 7 E 0 F I F F F F F F 7 Bonding Pairs of electrons and No Lone Pair electrons has this compound as a Pentagonal Bipyramid.

+ Electron Pair # Geometrical Arrangement Types of e- Pairs Molecular Shapes Ex’s Ball and Stick Model 7 Pentagonal Bipyramid 6 BP 1 LP Pentagonal Pyramidal IOF 5 -2 I – 7 valence e- 5 F – 35 valence e- O – 6 valence e- -2 charge – 2 valence e- Total = 50 valence e- Some elements can have EXPANDED Octets which means they can have more than the eight electrons around the central atom. AX 6 E 1 I O F F F F F 6 Bonding Pairs of electrons and One Lone Pair electrons has this compound as a Pentagonal Pyramidal.

+ Dotted Line and Wedge Model Linear AX 2 E 0 Trigonal Planar AX 3 E 0 Bent AX 2 E 1

+ Dotted Line and Wedge Model Tetrahedral AX 4 E 0 Trigonal Pyramidal AX 3 E 1 Bent AX 2 E 2

+ Dotted Line and Wedge Model Octahedral AX 6 E 0 Square Pyramid AX 5 E 1 Square Planar AX 4 E 2

+ Dotted Line and Wedge Model Pentagonal Bipyramid AX 7 E 0 Pentagonal Pyramid AX 6 E 1