shapes of simple molecules and ions

• linear bond angle

  180 degrees
• trigonal planar bond angle

  120 degrees
• non linear bond angle

  104.5 degrees
• pyramidal bond angle

  107 degrees
• tetrahedral bond angle

  109.5 degrees
• trigonal bipyramidal bond angle

  120 and 90 degrees
• octahedral bond angle

  90 degrees
• what is VSEPR and what does it predict ?

  • The valence shell electron pair repulsion theory (VSEPR) predicts the shape and bond angles of molecules
• electrons are -atively charged so will do what to other elections ?

  repel one another when close
• What causes a molecule to adopt a particular shape?

  The bonding pairs of electrons repel other electrons around the central atom, forcing the molecule to adopt a shape that minimizes these repulsive forces.
• What are the VSEPR rules to consider when determining the shape and bond angles of a molecule?

  • Valence shell electrons are found in the outer shell.
  • Electron pairs repel each other due to like charges.
  • Lone pair electrons repel more than bonded pairs.
  • Repulsion between multiple and single bonds is the same as single bonds.
• How do different electron pairs affect repulsion?

  • Lone pairs of electrons have a more concentrated electron charge cloud than bonding pairs.
  • The order of repulsion is: lone pair – lone pair > lone pair – bond pair > bond pair – bond pair.
• What is the most stable shape of a molecule and why?

  The most stable shape minimizes repulsive forces, as different electron pairs have different repulsive forces. Repulsion between double bonds is greater than single bonds.