1. 1 SCH4U - Introduction to Organic Chemistry *S*T*A*R*R*I*N*G**S*T*A*R*R*I*N*G**S*T*A*R*R*I*N*G**S*T*A*R*R*I*N*G* ALKANES The ALKANES ALKENES The ALKENES ALKYL Groups The ALKYL Groups Aromatic Compounds The Aromatic Compounds And all Their Little ISOMERS !

2. 2 And Co-Starring * S T R U C T U R E S * and F o r m u l a s With special mention to IUP AC The International Union of Pure and Applied Chemistry

3. 3 Structural Features of Carbon Compounds open-chainedcyclic The compound may be open-chained or cyclic. straightbranched Chains may be straight or branched. saturatedunsaturated May be saturated or unsaturated. carbocyclicheterocyclic Rings can be carbocyclic or heterocyclic. You will be dealing with ALL these cases at one time or another in this class!

4. 4 Structures and Chemical Formulas Molecular formulas are only useful for the very simplest compounds such as CH 4 or C 2 H 6, since they give no information on how atoms connect. There is usually more than one way to arrange the atoms listed in the molecular formula Expanded molecular formulas show atoms in the order that they appear, with brackets to indicate groups attached to chains. – ie) CH 3 C(CH 3 ) 2 CH 2 CH 3

5. More ways to represent... Organic compounds can be very complex! A system is needed that shows structure. Skeleton structures Expanded structures (full structural formulas) Condensed structural formulas Line representations

6. 6 Skeleton Structures Skeleton structure skeleton formula Skeleton structure or skeleton formula Leaves out the hydrogen atoms. For hydrocarbons, only the carbon skeleton and connecting bonds are shown. Bonds are represented as lines.. C – Example: Isobutane C-C-C

7. 7 Expanded Structural Formulas Expanded structural formula Expanded structural formula Shows all atoms with bonds. Bonds are represented as lines – Example Isobutane full Also called a full structural formula.

8. 8 Condensed Formulas Condensed formula Condensed formula Shorthand way of writing formula. Lists all atoms in order and tells how they are bound together. C-H bonds are assumed, not shown – Example: Isobutane

9. 9 Line Structural Diagrams Line formula line representation Line formula or line representation The end of each line or meeting point represents a carbon atom Hydrogen not shown, assumed Zig zag pattern for single and double bonds, triple bonds are in straight line Example: Isobutane

10. 10 Isomers Structural Isomers: Compounds with the same number of atoms and bonds but with different arrangements. – CH 3 CH 2 CH 2 CH 2 CH 3 CH 3 CH(CH 3 )CH 2 CH 3 (CH 3 ) 4 C

11. Geometric Isomers Compounds which have the SAME molecular formula, but different arrangements of atoms around a double carbon-carbon bond These exist when two or more arrangements are possible due to the type of bond. Alkanes Alkanes- can rotate about all bonds – no geometric isomers Alkenes Alkenes- rigid bond – can have geometric isomers Alkynes Alkynes- rigid bond but linear – no geometric isomers

12. 12 Geometric Isomers (continued) There are two possible arrangements Example 2-butene C=C H CH 3 H3CH3C H C=C CH 3 H H H3CH3C cis Two methyl groups are on the same side (and so are the two H’s. trans Two methyl groups are on opposite sides.