Living By Chemistry SECOND EDITION Unit 2: SMELLS Molecular Structure and Properties

Lesson 47: Mirror, Mirror Mirror-Image Isomers

ChemCatalyst Which of these objects looks identical in a mirror? Explain any differences. 1. glove 2. barbell 3. spring 4. tetrahedron

Key Question What are mirror-image isomers?

You will be able to: recognize mirror-image molecular structures explain what it means for molecules to be superimposable understand why mirror-image isomers have different properties

Prepare for the Activity Work in groups of four.

Discussion Notes Mirror-image molecules that cannot be superimposed on each other are called mirror-image isomers. Tetrahedral molecules in which four different atoms or groups are attached to a carbon atom always have mirror-image isomers.

Discussion Notes (cont.) The mirror-image isomers D-carvone and L-carvone have different smells. The mirror-image isomers have a “handedness.”

Wrap Up What are mirror-image isomers? Molecules that are not identical to their mirror image are called mirror-image isomers. Mirror-image isomers have a “handedness,” just like a right hand and a left hand. Mirror-image isomers can have different properties, including smell. Molecules that have at least one carbon atom with four different atoms or groups attached to it have a mirror-image isomer.

Check-In Which of these molecules will have a mirror-image isomer? Explain your reasoning. A. CF4 B. CHF3 C. C(CH3)4