Science, Tech, Math › Science How To Name Simple Alkene Chains Share Flipboard Email Print Science Photo Library / Getty Images Science Chemistry Molecules Basics Chemical Laws Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Todd Helmenstine Todd Helmenstine Todd Helmenstine is a science writer and illustrator who has taught physics and math at the college level. He holds bachelor's degrees in both physics and mathematics. Learn about our Editorial Process Updated on January 29, 2019 An alkene is a molecule made up entirely of carbon and hydrogen where one or more carbon atoms are connected by double bonds. The general formula for an alkene is CnH2n where n is the number of carbon atoms in the molecule.Alkenes are named by adding the -ene suffix to the prefix associated with the number of carbon atoms present in the molecule. A number and dash before the name denote the number of the carbon atom in the chain that begins the double bond.For example, 1-hexene is a six carbon chain where the double bond is between the first and second carbon atoms.Click image to enlarge the molecule. Ethene This is the chemical structure of ethene. ThoughtCo Number of Carbons: 2Prefix: eth- Number of Hydrogens: 2(2) = 4Molecular Formula: C2H4 Propene This is the chemical structure of propene. ThoughtCo Number of Carbons: 3Prefix: prop- Number of Hydrogens: 2(3)= 6Molecular Formula: C3H6 Butene This is the chemical structure of 1-butene. ThoughtCo Number of Carbons: 4Prefix: but- Number of Hydrogens: 2(4) = 8Molecular Formula: C4H8 Pentene This is the chemical structure of 1-pentene. ThoughtCo Number of Carbons: 5Prefix: pent- Number of Hydrogens: 2(5) = 10Molecular Formula: C5H10 Hexene This is the chemical structure of 1-hexene. ThoughtCo Number of Carbons: 6Prefix: hex- Number of Hydrogens: 2(6)= 12Molecular Formula: C6H12 Heptene This is the chemical structure of 1-heptene. ThoughtCo Number of Carbons: 7Prefix: hept- Number of Hydrogens: 2(7) = 14Molecular Formula: C7H14 Octene This is the chemical structure of 1-octene. ThoughtCo Number of Carbons: 8Prefix: oct- Number of Hydrogens: 2(8) = 16Molecular Formula: C8H16 Nonene This is the chemical structure of 1-nonene. ThoughtCo Number of Carbons: 9Prefix: non- Number of Hydrogens: 2(9) = 18Molecular Formula: C9H18 Decene This is the chemical structure of 1-decene. ThoughtCo Number of Carbons: 10Prefix: dec- Number of Hydrogens: 2(10) = 20Molecular Formula: C10H20 Isomer Numbering Scheme This shows three isomers of the hexene alkene molecule: 1-hexene, 2-hexene and 3-hexene. The carbons are numbered from left to right to show the location of the carbon double bonds. ThoughtCo These three structures illustrate the numbering scheme for isomers of alkene chains. The carbon atoms are numbered from left to right. The number represents the location of the first carbon atom that is part of the double bond.In this example: 1-hexene has the double bond between carbon 1 and carbon 2, 2-hexene between carbon 2 and 3, and 3-hexene between carbon 3 and carbon 4.4-hexene is identical to 2-hexene and 5-hexene is identical to 1-hexene. In these cases, the carbon atoms would be numbered from right to left so the lowest number would be used to represent the molecule's name. Cite this Article Format mla apa chicago Your Citation Helmenstine, Todd. "How To Name Simple Alkene Chains." ThoughtCo, Aug. 28, 2020, thoughtco.com/how-to-name-simple-alkene-chains-608215. Helmenstine, Todd. (2020, August 28). How To Name Simple Alkene Chains. Retrieved from https://www.thoughtco.com/how-to-name-simple-alkene-chains-608215 Helmenstine, Todd. "How To Name Simple Alkene Chains." ThoughtCo. https://www.thoughtco.com/how-to-name-simple-alkene-chains-608215 (accessed June 8, 2023). copy citation