LEcture 20 - Isomers

Flashcards covering key concepts related to isomers, including definitions, properties, and types.

What are constitutional isomers?

Isomers that differ in the nature or sequence of bonding.

How do the physical and chemical properties of constitutional isomers compare?

They vary rapidly.

What are stereoisomers?

Isomers that differ in the arrangement of groups in space but have the same nature and sequence of bonding.

What are configurational isomers?

Isomers that have the same order of atoms connected but differ in their spatial arrangement.

What is required to interconvert configurational isomers?

You must break and reform bonds, which requires a lot of energy.

What differentiates conformational isomers?

They differ by rotation about a single C-C bond and are normally separable at room temperature.

What happens if both ends of a C=C bond have two different groups attached?

Two diastereoisomers will be created.

How do you assign priority to groups on a C=C bond?

The higher the atomic number of the atom attached, the higher the priority.

What is indicated by a Z double bond?

High priority groups on the same side of the C=C bond.

What is indicated by an E double bond?

High priority groups on opposite sides of the C=C bond.

What describes the staggered conformation of ethane?

Hydrogens are as far apart as possible, making it the lowest energy (most stable) configuration.

What describes the eclipsed conformation of ethane?

Hydrogens are lined up with each other, making it the highest energy (least stable) configuration.

What are Newman projections?

A way to draw the 3D arrangement of atoms around a single bond as if looking directly along the axis of a carbon-carbon bond.

What are barriers to rotation in alkanes?

Differences in energy arise from steric interactions during rotation about C-C bonds.

What is the relationship between constitutional and structural in isomer terminology?

Constitutional isomers are also referred to as structural isomers.

What is the relationship between configurational and stereoisomers in isomer terminology?

Configurational isomers are a type of stereoisomer.