IUPAC Nomenclature Rules

• Worked example: 3 carbons in the longest chain = prop, has an -OH functional group = alcohol, has a methane group on 2nd carbon = 2-methyl, resulting in the name 2-methylpropanol.
• Stereoisomerism occurs due to the restricted rotation of C=C double bonds and can be in the form of E and Z (CIS and TRANS) isomers.
• C4H8Br2 has 3 structural isomers: 1,2-dibromobutane, 1,3-dibromobutane, and 2,3-dibromobutane. It exhibits positional isomerism.
• Homologous series: A set of organic compounds with the same functional group, differing in the length of their hydrocarbon chains.
• Functional group: An atom or group of atoms in an organic molecule responsible for the characteristic reactions of that molecule.
• Use commas between numbers and dashes between numbers and letters.
• When arranging substituent groups in alphabetical order, do not count prefixes like di, tri, tetra.
• It is often impossible to distinguish between different functional groups by visual inspection and tests may be required for identification.
• Structural isomerism is when molecules have the same molecular formula but different structural formulae.
• Positional isomers are compounds with the same molecular formula but the functional group is in a different position.
• Functional group isomerism is when molecules have the same molecular formula but different functional groups.
• Isomers have similar chemical properties, but may have slightly different physical properties.
• PENT-1-ENE has a double bond between carbons 1 and 2, while PENT-2-ENE has a double bond between carbons 2 and 3.
• Molecules can rotate freely around single C-C covalent bonds, but not around C=C double bonds.
• Z-but-2-ene and E-but-2-ene are examples of E-Z isomers.
• The highest priority groups are on the opposite side of the double bond in E (trans) isomers.
• The highest priority groups are on the same side of the double bond in Z (cis) isomers.
• The higher the atomic number, the higher the priority.
• Stereoisomers have the same structural formula, but atoms occupy different positions in space.
• Empirical formula is the simplest whole number ratio of atoms of each element in a compound
• Molecular formula is the actual number of atoms of each element present in a compound
• 1. find and name the longest continuous carbon chain
  2. identify and name functional groups/side chains attached to this chain 
  3. number the chain consecutively, starting at the end nearest the functional group so the functional group sits on the lowest possible
  4. Make a note of the carbon number the functional group is attached to and place this number before the suffix e.g. butan-1-ol
  5. Any side chains and less important functional groups are written as prefixes in alphabetical order 
  6. if there is more than one identical functional group or side chain put di- (2), tri- (3), tetra- (4)
• Chain isomers have the same molecular formula, but different arrangements in the carbon skeleton.