1. Intro to organic chemistry
SCH4U – Unit 1

2. Organic Compounds Organic chemistry: chemistry of carbon compounds
Exceptions are oxides of carbon (CO2 and CO), carbonates, bicarbonates, and cyanides
Carbon atoms are generally bonded to:
Each other
Hydrogen atoms
Other specific elements (O, N, S, P and others)

3. Why study organic chemistry?
Life is carbon-based. Everyone is made up of organic compounds. There are more known carbon compounds than any other element.
There are several million known organic compounds with ~30,000 more being “discovered” each year.
Some common organic compounds include plastics, synthetic and natural fibres, dyes, drugs, pesticides, lighter fluid, and gasoline.

4. The carbon atom
Carbon has four valence electrons allowing it to form four bonds with other atoms by sharing its electrons
This results in a tetrahedral shape
Carbon forms covalent bonds (sharing of electrons) with carbon atoms

5. Classification
Since organic compounds are composed almost entirely of carbon, they are sometimes referred to as hydrocarbons
Hydrocarbons can be divided into:
Aliphatics: carbon atoms in an open chain structure; may have branches, but no rings
Alicyclics: carbon atoms arranged in a ring structure
Aromatics: structures related to benzene (C6H6)

6. Classification Aliphatics can be further categorized into:
Alkanes: contains only single bonds (saturated)
Alkenes: contains at least one double bond (unsaturated)
Alkynes: contains at least on triple bond

7. Diagrams & formulas
A number of different (but related) diagrams used to express structures in organic chemistry:
Empirical molecular formula
Expanded molecular formula
Complete structural formula
Condensed structural formula
Line structural formula
3D structural formula

8. Alkanes # of carbons Prefix 1 Meth- 6 Hex- 2 Eth- 7 Hept- 3 Prop- 8
Oct- 4
But- 9
Non- 5
Pent- 10
Dec-

9. Alkanes Only single bonds present in the main chain
General formula is CnH2n+2
Form a tetrahedral shape
Note: more on shapes in the next unit
Create a 109.5° angle between bonds
Considered “saturated” because no other hydrogen atoms can be added
Always end in “~ane”

10. Nomenclature Three parts to organic chemistry nomenclature:
Prefix: indicates number, type and location of branches and/or functional groups (if any)
Root: indicates the number of carbon atoms in the main (parent) chain
Suffix: indicates the number and location of double or triple bonds (if any) and/or highest priority functional group

11. Let’s draw alkanes!
Draw all ten basic alkanes and name them.

12. Alkyl groups and branching
Each branch of a hydrocarbon is referred to as an alkyl group (if it contains only C and H)
Alkyl groups use the same basic roots as alkanes
Alkyls always end in “~yl”
Also contain a number and hyphen in front to indicate location on the main carbon chain
Example: 2-methyl pentane

13. Alkyl groups and branching
Find the longest carbon chain and assign sequential numbers to each carbon
Assign these numbers temporarily starting from both ends of the carbon chain
Ultimately will select only one set of numbers to use
The goal is to use the numbering along the carbon chain that gives the lowest values assigned to branches

14. Alkyl groups and branching
Let’s try some! Draw 3-ethyl octane…

15. Alkyl groups and branching

16. Alkyl groups and branching
When there is more than one branch, they are listed in front of the root and suffix according to alphabetical order of the name of the alkyl group
Try naming…
4-ethyl 3-methyl heptane

17. Alkyl groups and branching
If there is more than one of any given alkyl group
Indicate all the number for the positions using commas to separate the numbers, and
Use prefixes (on the prefixes – confused yet?) to indicate the number present

18. Alkyl groups and branching
Try naming…
5,6-diethyl-3,3,4-trimethyl nonane