Question

How do geometrical isomers differ in their properties due to difference in spatial arrangement of atoms or groups of atoms?

Answer 1

Geometrical isomers have carbon-carbon double bonds due to which there is no free rotation around the bond. The position of the groups attached at the carbons form the geometrical isomers i.e. cis and trans isomers.
Cis-isomer has the main priority groups at the same side and trans-isomers have at the opposite sides.
Geometrical isomers have different properties like melting and boiling point. If we compare the melting point then the trans isomer will have high melting point and cis-isomer will have boiling point higher than the trans-isomer. This is because melting point depends on the packing in the crystal lattice. The one which is closely packed would have high melting point. On the other hand, boiling point depends on the surface area. More is the surface area, more will be the boiling point.
The main difference between the properties arises due to their polarity. Trans isomers have lower polarity than the cis-isomers. CIs-isomer is always polar.
So, the properties are different due to difference in the spatial arrangement of atoms.