2.4 - Organic compounds

• What doers the term 'organic' in terms of compounds mean?

  Carbon containing
• An organic molecule in which the carbon atoms forms continuous chain is called what?

  Straight chain molecule
• How are organic molecules named?

  1. Look for longest carbon chain - this will be the base name
  2. Look for shorter carbon branches and assign a name to them (methyl, ethyl, etc.)
  3. State the number of identical branches using di-, tri-, tetra- etc.
  4. Assign numbers to the carbons in the longest chain and indicate which carbon the branches are attached to
• Skeletal formula:

  The simplified displayed formula with the carbon-hydrogen bonds removed.

  For example...

  
• Displayed formula:

  Shows all of the atoms and how they are bonded in an organic compound. For example...

  
• Structural formula:

  A structural formula shows how the atoms in a molecule are joined together in written form, they do not include lines to show individual bonds like the displayed formula. For example...

  
• Molecular formula:

  A molecular formula indicated simply the number of each type of atom present in an organic molecule, but gives no information on their structure. For example:

   C 6H 12O 6
• Empirical formula:

  The simplest whole number ratio of each element present in a compound
• What does the term homologous series mean?

  A series or organic compounds with the same fucntional group and similar chemical properties.
• The properties of a homologous series are...

  • The members of such a series are able to be represented by a general formula
  • Each member differs from its neighbours by CH2
  • There is a gradual trend in physical properties such as melting or boiling points along the series
• Isomers:

  Different compounds with the same molecular formula
• What are the 2 main types of isomers?

  • Structural isomerism
  • Stereoisomerism
• What does structural isomerism mean?

  Different arrangements of the atoms in a molecule so that they have a different structural formulae
• Give the three sub-types of structural isomerism:

  • Chain
  • Position
  • Functional group
• Define chain isomerism:

  Different arrangements of the carbon chain
• Define position isomerism:

  Same carbon skeleton but functional groups occupy different positions
• Define functional group isomerism:

  Have the same molecular formulae but have different functional groups so belong to a different homologous series
• What does stereoisomerism mean?

  Same structural formula but the 3D arrangement/spatial arrangement of atoms is different.
• E-Z isomerism is a form of stereoisomerism, what is this also sometimes called?

  Geometric isomerism
• For E-Z isomerism to be possible, what must the compound have?

  • A double carbon bond to prevent free rotation
  • Each carbon in the double bond must have 2 different groups attached
• E (entgegan):

  Highest priority (higher atomic number) are diagonally opposite each other
• Z (zusammen):

  Highest priority (higher atomic number) are together
• Structural isomers have different physical properties, give some examples:

  • Melting point
  • Boiling point
  • Solubility
• What is a free radical?

  An atom or molecule with an unpaired electron (or more)
• What is a nucleophile?

  A species with a lone pair of electrons that attack regions of low electron density. They donate electrons to an electrophile.
• What is an electrophile?

  A species that is electron deficient and attacks regions of high electron density. Electrophiles accept electrons from nucleophiles.
• Homolysis/homolytic fission:

  A covalent bond breaks and each atom retains one of the shared pair of electrons in the covalent bond. EQUAL SPLITTING
• Heterolysis/heterolytic fission:

  A covalent bond breaks and one of the atoms retains both of the pair of shared electrons in the covalent bond. UNEQUAL SPLITTING