Isomerism

What are structural isomers?

Molecules with the same molecular formula but different structural formulae.

What are stereoisomers?

Compounds with the same structural formula but a different arrangement of the atoms in the space.

Why does stereoisomerism occur around C=C bonds?

Rotation around the C=C bond is restricted and groups attached to each carbon atom in the C=C bond are therefore fixed relative to each other.

What is the reason for the rigidity of a C=C bond?

The pi bond in the C=C bond has electron density above and below the plane of the sigma bond.

What are the conditions for stereoisomerism?

C=C bond.

Different groups attached to each C atom of the C=C bond.

What are the conditions for Cis/Trans isomerism?

C=C bond.

Different groups attached to each C atom of the C=C bond.

One group attached to each C atom in the C=C bond must be the same.

What are the conditions for optical isomerism?

The molecule must contain at least one chiral carbon atom.

What is a chiral carbon?

A carbon atom attached to 4 different atoms or groups of atoms.

What are optical isomers?

Stereoisomers that are non-superimposable mirror images of each other.

If there are n chiral carbon atoms in a molecule, how many optical isomers does the molecule have?

2^n