Organic Chemistry AQA CHEM2

homologous series...same functional group, differ by CH2

CnH2n

UNSATURATED

Obtained by cracking

Bromine goes colourless if an alkene is present

C=C is a region of high electron density

structure restricts C=C bond so ethene is a planar molecule

with Bromine

...goes colourless

...Br is added across the C=C

same structural formula, different arrangement of atoms

alkenes demonstrate a stereoisomer called geometric stereoisomer

Geometric Stereoisomers

Have restricted rotation

CH₃ on the same side = Z-but-2-ene

CH₃ on different sides = E-but-2-ene