basic concepts

• Skeletal formula

  A simplified organic formula, with hydrogen atoms removed from alkyl chains leaving just a carbon skeleton and associated functional groups.
• Structural formula

  A formula showing the minimal detail for the arrangement of atoms in a molecule.
• Structural isomers

  Compounds with the same molecular formula but different structural formulae.
• Molecular formula


  A formula that shows the number and type of atoms of each element present in a molecule
• Nomenclature


  A system of naming compounds
• Alicyclic


  Containing carbon atoms joined together in a ring that is not aromatic
• Aliphatic


  Containing carbon atoms joined together in unbranched (straight) or branched chains
• Alkyl group

  A side chain formed by removing a hydrogen atom from an alkane parent chain. Any alkyl group is often shown as 'R'
• Alkynes

  The hydrocarbon homologous series with at least one triple carbon-to-carbon bond
• Aromatic


  Containing one or more benzene rings
• Displayed formula

  A formula that shows the relative positioning of all the atoms in a molecule and the bonds between them
• Empirical formula

  A formula that shows the simplest whole-number ratio of atoms of each element present in a compound
• Functional group

  The part of the organic molecule responsible for its chemical reactions
• General formula

  The simplest algebraic formula of a member of a homologous series
• General formula for the alkanes is CnH2n+2
• General formula for alkenes is CnH2n
• General formula for cycloalkanes is CnH2n
• General formula for alkynes is CnH2n-2
• Homologous Series

  series of compounds with the same functional group with each successive member differing by CH2
• alicyclic compounds are also considered aliphatic