1. Highland Science Department Molecule Shapes Why do these molecules have such different shapes?

2. Highland Science Department Molecule Shapes recall:bonding pair: e - pairs involved in bonding lone pair: e - pairs not involved in bonding

3. Highland Science Department Molecule Shapes recall:bonding pair: e - pairs involved in bonding lone pair: e - pairs not involved in bonding VSEPR Theory: Valence Shell Electron Pair Repulsion Theory

4. Highland Science Department Molecule Shapes VSEPR Theory: Valence Shell Electron Pair Repulsion Theory -electron pairs are arranged around atoms so that they are a maximum distance from each other in 3 dimensional space

5. Highland Science Department Molecule Shapes VSEPR Theory: Valence Shell Electron Pair Repulsion Theory -electron pairs are arranged around atoms so that they are a maximum distance from each other in 3 dimensional space -from Lewis diagrams we know atoms want a stable octet (4 pairs of electrons) -shapes come from how many of those are bonding pairs & how many are lone pairs -double & triple bonds also have an effect

6. Highland Science Department Molecule Shapes Tetrahedral: an atom bonded to four other atoms spaced as far apart as possible will create 109.5 o angles

7. Highland Science Department Molecule Shapes Tetrahedral: an atom bonded to four other atoms spaced as far apart as possible will create 109.5 o angles e.g. carbon tetrachloride (CCl 4 ) in 3-D is

8. Highland Science Department Molecule Shapes Pyramidal: if there are one lone pair and three bonding pairs, the lone pair will exert a repulsion on the bonding pairs, resulting in a pyramidal shape δ - δ +

9. Highland Science Department Molecule Shapes Pyramidal: if there are one lone pair and three bonding pairs, the lone pair will exert a repulsion on the bonding pairs, resulting in a pyramidal shape e.g. ammonia (NH 3 ) δ - in 3-D is δ +

10. Highland Science Department Molecule Shapes Bent: two lone pairs will force the bonding pairs towards each other and form a bent shape lone pairs bonding pairs

11. Highland Science Department Molecule Shapes Bent: two lone pairs will force the bonding pairs towards each other and form a bent shape e.g. water (H 2 O) δ - in 3-D is δ +

12. Highland Science Department Molecule Shapes Linear: double bonding the three atoms removes the lone pairs and makes a linear molecule

13. Highland Science Department Molecule Shapes Linear: double bonding the three atoms removes the lone pairs and makes a linear molecule e.g. carbon dioxide (CO 2 ) δ - δ + δ - in 3-D is

14. Highland Science Department Molecule Shapes Polarity of Molecules: Polar Molecule: a molecule with a positive end and a negative end e.g.water (H 2 O) δ - δ +

15. Highland Science Department Molecule Shapes Polarity of Molecules: Non-Polar Molecule: a molecule where all ends are equally charged e.g.carbon dioxide (CO 2 ) δ - δ + δ - -each end is equally negative so the overall molecule is non-polar

16. Highland Science Department Molecule Shapes Intramolecular Forces: forces that hold the atoms in a molecule together Intermolecular Forces: forces that attract molecules to other molecules

17. Highland Science Department Molecule Shapes Intramolecular Intermolecular