IUPAC nomenclature of unsaturated hydrocarbons (Alkenes and Alkynes)

Naming alkenes (carbon-carbon double bonds) and alkynes (carbon-carbon triple bonds) uses every rule already given for alkanes, PLUS several additional rules specific to the multiple bond itself. RULE 1: the longest continuous chain chosen as the parent MUST include the carbon-carbon multiple bond -- even if a longer chain exists elsewhere in the molecule that happens not to pass through that multiple bond, the multiple-bond-containing chain still wins and becomes the parent. RULE 2: the parent chain is numbered in whichever direction gives the multiple bond the LOWEST possible locant number. RULE 3: the alkane ending '-ane' is replaced by '-ene' if the multiple bond is a double bond, or by '-yne' if it is a triple bond. RULE 4: the single locant number written immediately before that '-ene'/'-yne' ending is always the LOWER-numbered of the two multiply-bonded carbons -- so CH3-CH2-CH=CH2 is but-1-ene (the double bond starts at C-1, counting from the end nearer it) and HC≡C-CH2-CH3 is but-1-yne. RULE 5: if the multiple bond happens to sit exactly equidistant from both ends of the chosen parent chain (so rule 2 alone cannot decide the numbering direction), numbering instead starts from whichever end is nearer the FIRST branch point (the first substituent) along the chain. RULE 6: a chain containing TWO double bonds, or TWO triple bonds, is named with the ending '-diene' or '-diyne' respectively (note that the 'a' of the underlying '-ane' stem is deliberately kept in this case, e.g. 'penta-' not 'pent-'), with both locants cited together -- for example penta-1,3-diene, CH3-CH=CH-CH=CH2, or hexa-1,4-diyne, CH3-C≡C-CH2-C≡CH. RULE 7: a chain containing BOTH a double bond and a triple bond is numbered from whichever end brings A multiple bond (either kind) in sooner, and is named by writing the '-en-' ending first, followed directly by the '-yne' ending, with each multiple bond's own locant number placed immediately before its own ending -- for example pent-1-en-3- …