Stereoisomerism in alkenes

C-C:

L... bond - can r...

C=C:

S... bond - r... - restricted r...

longer, rotate, shorter, rotation

C=C = rigid so 2 possibilities are produced- these have the same s... ... but different a... of atoms

structural formula, arrangement

Requirements for stereoisomerism:

A .... double bond +

Each carbon must have 2 ... groups attached to it

C=C, different

If 2 identical groups attached to one carbon, then NO s...

stereoisomerism

Stereoisomerism = used when there's 2 i... groups attached to each carbon

identical

Cis: identical groups = attached on ... side of double bond

e.g both = bottom

same

Trans: identical groups = attached on o... sides across double bond

e.g one top, one bottom

opposite

If there are 4 different groups, we use ...

We assign ... to groups attached to each carbon on C=C bond to determine which.

E/Z, priorities

Higher priority = higher ... ...

e.g I>Br>Cl>F>C>H

atomic number

Z = higher priority atoms on ... side

E = higher priority atoms on ... sides

(zame + enemy)

same, opposite

To determine priority, look at ... ... of atoms DIRECTLY attached to carbons in C=C, NOT whole branch

atomic number

Both E/Z + Cis/Trans can occur only if both C atoms of C=C have two ... groups

different

σ covalent bond: ... overlap of orbitals - strong - electrons = between C=C

π covalent bond: ... overlap of p-orbitals - weaker/reactive - electrons above + below 6 central atoms

direct, sideways

Optical isomers: C atoms have 4 ... groups attached - non superimposable mirrored

different