Name the following molecules according to the IUPAC nomenclature rules.

SOLUTION:

Molecule 1.

Main chain: 5-membered cycle (cyclopentane).
Numbering: ethyl locant 1 (comes before alphabetically).
Substituents: ethyl in 1; isopropyl in 3.
Name: trans-1-Ethyl-3-isopropylcyclopentane.
Note: the particle trans indicates that the substituents go to opposite sides

Molecule 2.

Main chain: 6-membered cycle (cyclohexane).
Numbering: locant 1 to bromine (comes before alphabetically).
Substituents: bromo in 1; methyl in 4.
Name: cis-1-Bromo-4-methylcyclohexane.
Note: the cis particle indicates that the substituents are on the same side.

Molecule 3.

Main chain: 10-membered cycle (cyclodecane).
Numbering: cyclopentyl locant 1 (comes before alphabetically).
Substituents: 1-cyclopentyl and 5-methyl.
Name: trans-1-Cyclopentyl-5-methylcyclodecane.

Molecule 4.

Main chain: 5-membered cycle (cyclopentene).
Numbering: locant 1 to the double bond. Numbering continues to give the lowest locant to methyl.
Substituents: methyl in position 3.
Name: 3-Methylcyclopentene.