Shapes of molecules

• How many bonding pairs does linear have?

  2
• Linear - 2 BP, 0 LP, 180 degrees
• How many lone pairs does linear molecule have?

  0
• What is the bond angle of a linear molecule?

  180
• Trigonal planar - 2 BP, 0 LP, 120 degrees
• How many bond pairs does a trigonal planar molecule have?

  3
• How many lone pairs does a trigonal planar molecule have?

  0
• What is the bond angle for a trigonal planar molecule?

  120
• Pyramidal - 3 BP, 1 LP & 107 degrees
• How many bond pairs does a pyramidal molecule have?

  3
• How many lone pairs does a pyramidal molecule have?

  1
• what is the bond angle for a pyramidal molecule?

  107
• Tetrahedral - 4 BP, 0 LP, 109.5 degrees
• How many bond pairs does a tetrahedral molecule have?

  4
• How many lone pairs does a tetrahedral molecule have?

  0
• What is the bond angle for a tetrahedral molecule?

  109.5
• Octahedral - 6 BP, 0 LP, 90 degrees
• How many bond pairs does an octahedral molecule have?

  6
• How many lone pairs does an octahedral molecule have?

  0
• What is the bond angle for an octahedral molecule?

  90
• Angular - 2BP, 2 LP, 104.5 degrees
• How many bond pairs does an angular molecule have?

  2
• How many lone pairs does an angular molecule have?


  2
• What is the bond angle of an angular molecule?

  104.5
• For every lone pair the bond angle will reduce by 2.5 degrees as electron pairs repel more strongly
• By how many degrees do lone pairs decrease the bond angle?

  2.5
• Why do lone pairs decrease the bond angle by 2.5 degrees?

  Electron pairs repel more strongly
• Why is the bond angle 107 degrees and not 109.5 degrees in ammonia?

  lone pairs repel more strongly than bond pairs

  so lone pairs pushes N-H bonds closer

  Each lone pair closes the bond in a molecule by 2.5 degrees

  Therefore the bond angle is reduced from 109.5 - 2.5 = 107