3.3.4.1 Structure, bonding and reactivity

• Aliphatic hydrocarbons

  Branched or unbranched chains of carbon atoms, rings of hydrocarbons
• Why would you expect alkenes and cycloalkanes to have similar reaction?

  Belong to the same homologous series, undergo the same chemical reactions
• Type of IMF in alkenes

  Random movement of electrons, temporary dipole-dipole can induce dipole
• Define an isomer

  Same molecular formula but a different structure, arrangement of atoms and different properties
• What does bonding in alkene involve?

  Double covalent bond and a high density of electrons
• How are the covalent bonds formed>

  Overlap of orbitals
• Name the 2 types of bond

  Pi and sigma bonds
• What is the bond angle between the covalent bonds?

  120
• How is a sigma bond formed?

  Overlap of s-orbitals
• How is a pi bond formed?

  Sideways overlap of p orbitals
• What bond requires more energy to break

  sigma bond
• Why does the double bond in ethene require more energy to break than ethane

  Contains a pi and sigma bond
• Define stereoisomer

  Molecules with the same molecular and structural formula but different arrangement of atoms
• Name the types of stereoisomerism

  Geometrical and optical
• How are E-Z isomers formed

  Molecules with a C=C with 2 different groups attached to each C of the C=C
• Name the 3 types of structural isomerism

  Positional, chain and function
• Why do E- isomers exist

  Due to the restricted rotation about the C=C bond
• Why do E-Z isomers have different physical properties

  Different structural formulas
• How do we decide which groups have higher priority

  Atomic number
• What is the CIP rules

  Atom with the highest number is given the higher priority
• Which has a greater boiling point cis or trans?

  Trans as their molecules have the ability to pack tightly in the solid state