1. Chapter 20: Carbon and Hydrocarbons
20.1 – Abundance and Importance of Carbon
20.2 – Organic Compounds
20.3 – Saturated Hydrocarbons
20.4 – Unsaturated Hydrocarbons

2. Structure and Bonding of Carbon
Carbon, the first member of Group 14, has mostly nonmetallic properties. Carbon atoms tend to form four single bonds. This bonding results in a tetrahedral shape.

3. Allotropes of Carbon
Carbon occurs in several solid allotropic forms that have dramatically different properties.
Diamond – Colorless, crystalline, solid form of carbon
Graphite – soft, black, crystalline form of carbon that is a fair conductor of electricity.
Fullerenes – dark colored solids made of spherically networked carbon atom cages

4. Allotropes of Carbon - Diamond
The hardest material known to man
Carbon atoms are bonded covalently in a network fashion
Conducts heat 5x better than silver or copper
Does not conduct electricity

5. Allotropes of Carbon - Graphite
Soft, crumbles easily and feels greasy
Used as a lubricant and as lead
Good conductor of electricity
Stronger and lighter than steel

6. Allotropes of Carbon - Fullerenes
Discovered in the 1980s (N.P. 1996)
Structure consists of near spherical cages
Scientists are currently trying to find practical uses for these substances

7. Organic Compounds
Covalently bonded compounds containing carbon, excluding carbonates and oxides
The diversity of organic compounds results from the uniqueness of carbon’s structure and bonding

8. Carbon – Carbon Bonding
Catenation – Carbon atoms are unique in their ability to form long chains and rings of covalently bonded atoms.

9. Carbon Bonding to Other Elements
Hydrocarbons – composed of only carbon and hydrogen; they are the simplest organic compounds.
Most contain hydrocarbon backbones and have other elements added on (O, S, and N)

10. Arrangement of Atoms
Isomer – Compounds that have the same molecular formula but different structures
As the number of carbons increases so does the number of possible isomers

11. Structural Formula
Indicates the number and types of atoms present in a molecule and also shows the bonding arrangement of the atoms
Structural formulas do not accurately represent the three dimensional shape of the molecule.

12. Isomers – Structural
Structural Isomers – isomers in which the atoms are bonded together in different orders

13. Isomers - Geometric
Isomers in which the order of atom bonding is the same but the arrangement of atoms in space is different
In order for geometric isomers to exist, there must be a rigid structure in the molecule to prevent free rotation around a bond

14. Cis and Trans

15. Saturated Hydrocarbons
Hydrocarbons in which each carbon atom in the molecule form four single covalent bonds with other atoms

16. Alkanes CnH2n+2 Hydrocarbons that contain only single bonds
Homologous series – one in which adjacent members differ by a constant unit.
Alkyl groups- groups of atoms that are formed when one hydrogen atom is removed from an alkane molecule

17. Cycloalkanes
Alkanes in which the carbon atoms are arranged in a ring, or cyclic, structure

18. Alkane Nomenclature Unbranched Chain
Count the longest continuous chain.
Use greek prefix (at right)
End with -ane

19. Alkane Nomenclature Branched Chain
Name the longest chain (See previous)
Add the name of the alkyl group
Insert position numbers
Punctuate

21. Example

22. Cycloalkane Nomenclature
Name the longest chain
Add Cyclo-
Add names of alkyl groups
Number the carbons (lowest numbers)
Inset position numbers
Punctuate

23. Example Give the name of the following molecule 6 carbons = hexane
CH3 = methyl
Number around the circle
1,3 - dimethlycyclohexane

24. Example
Draw 1,1- dimethylcyclobutane

25. Unsaturated Hydrocarbons
Hydrocarbons in which not all carbon atoms have four single covalent bonds

26. Alkenes CnH2n
Hydrocarbons that contain double covalent bonds

27. Alkene Nomenclature Name the same as Alkane
Locate the longest continuous chain that contains the double bond(s).
Double bond should have lowest number

28. Example

29. Alkynes CnH2n-2 Hydrocarbons with triple covalent bonds
Named the same as others
Find the longest chain containing a triple bond
Number so triple bond has lowest number

30. Example
Name the following

31. Aromatic Hydrocarbons
Hydrocarbons with six membered carbon rings and delocalized electrons
Benzene – the primary aromatic hydrocarbon

32. Aromatic Nomenclature
Name the parent Hydrocarbon (Usually benzene)
Name the Alkyl groups
Number the carbon atoms
Insert position numbers
Add Punctuation

33. Example
Name the following

34. Example