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Part 1: Alkane, Alkene, and Alkyne

Part 2: Isomers

REVIEW

What is an alkane?

The most basic hydrocarbons containing all single bonds.

What are some examples?

SATURATED VS UNSATURATED

Organic compounds that contain the maximum number of hydrogen atoms per carbon atom are called saturated compounds.

Organic compounds that contain double or triple carbon-carbon bonds are called unsaturated compounds.

ALKENES AND ALKYNES

1) Alkane: All carbon-carbon bonds are single covalent bonds. (Saturated Compounds)

2) Alkene: At least one carbon-carbon bond in an alkene is a double covalent bond. (Unsaturated Compounds)

3) Alkyne: At least one carbon-carbon bond in an alkyne is a triple covalent bond. (Unsaturated Compounds)

EXAMPLES OF ALKENES

Compare to Alkane derivative

EXAMPLE OF ALKYNES

If you see at least triple bond like the one above in the hydrocarbon, it is an alkyne.

NAME CHANGES…

What is the alkane, alkene, and alkyne versions of a hydrocarbon containing 4 carbons?

PART 2: ISOMERS

The retinal molecule in the rod and cone cells of your eye has a hydrocarbon skeleton. When light strikes a cell containing retinal, it causes a change in the three-dimensional structure of the retinal molecule. The structures before and after the light strikes are examples of isomers. You will study different types of isomers.

ISOMER? WHAT IS IT?

Compounds that have the same molecular formula but different molecular structures are called isomers.

Two types of isomers:

1) Structural Isomers

2) Stereoisomers

ISOMER 1: STRUCTURAL ISOMERS

Structural isomers are compounds that have the same molecular formula, but the atoms are joined together in a different order.

Both butane and 2-methylpropane have the molecular formula C4H10. The atoms in their molecules are arranged in a different order, so they are structural isomers.

ISOMER 2: STEREOISOMERS

Stereoisomers are molecules in which the atoms are joined in the same order, but the positions of the atoms in space are different.

Two types of stereoisomers:

1) Geometric Isomers

2) Optical Isomers:

GEOMETRIC ISOMER:

Geometric isomers have atoms joined in the same order, but differ in the orientation of groups around a double bond.

Trans: alkyl groups on opposite sides with double bond between

Cis: alkyl groups on same side with double bond between.

PRACTICE:

Which is the the trans and cis configuration for butene….

OPTICAL ISOMER:

Pairs of molecules that differ only in the way that four different groups are arranged around a central carbon atom are called optical isomers.

They are “mirror’ images of each other that cannot be superimposed.

These carbons are assymetric carbons: Have four DIFFERENT groups bonded to the carbon.

CHALLENGE

What are some objects that CAN be superimposed after being reflected in a mirror?

These examples would NOT be optical isomers.

Now superimpose CH3CH2CH3

What are some objects that CANNOT be superimposed after being reflected in a mirror?

These examples would be optical isomers.