Shapes and bond angles

• What is the electron repulsion theory?

  Eleectons have the same charge and so repell as far each other as far apart as possible determaning the molecuels shape
• How do lone pairs affect bond angles?

  They repel more then bonding pairs so the electrons are pushed together causing the lone pair to decrease the bong angle by -2.5
• What is the order of bond repulsion form most repelling to least?

  Lone-lone, lone-bond, bond-bond
• How do you determine the shape of molecules?

  - find the number of outer shell electrons on the central atom

  - plus or minus this number if it's an ions

  - to find the number of lone pairs take away the single bonds from number of electrons and divide by 2
• Draw and name the shape of carbon dioxide and write the bond angle

  
• Draw and name the shape of a ammonium ion and write the bond angle

  
• Draw and name the shape of a nitrate ion and write the bond angle

  
• Draw and name the shape of a carbonate ion and write the bond angle

  
• Draw and name the shape of a sulphate ion and write the bond angle

  
• What are the shapes and bond angels?

  Linear = 2 bonded pairs = no lone pairs = 180

  Trigonal planar = 3 bonded pairs = no lone pairs = 120

  Tetrahedral = 4 bonded pairs = no lone pairs = 109.5

  Non linear = 2 bonded pairs = 2 lone pairs = 104.5

  octahedra = 6 bonded pairs = no lone pairs = 90

  Pyramidal = 3 bonded pairs = 1 lone pairs = 107
• What is electronegativity?

  a measure of the tendency of an atom to attract a bonding pair of electrons
• What does a high electronegative value indicate?

  That the bonded atom is attracted the the electrons more
• What are the trends in electronegativity across the periodic table?


  Increases across a period

  Increases up a group
• How can we used Pauling values to indicate the bond?

  0 = covalent

  0-1.8 = polar covalent

  1.8+ = ionic
• What is the Pauling scale?


  Gives number for electronegativity
• What is a polar bond?


  a covalent bond in which electrons are shared unequally leading to a permanent dipole
• What is a non-polar molecule?


  molecule that shares electrons equally and does not have oppositely charged ends, and is symmetrical so dipoles are cancelled
• If a molecule has a lone pair what type of bond will it have?


  Polar as it cause the molecule to become unsymmetrical
• What does a great electronegativity difference lead to?

  A more polar bond and so creates partial charges
• How do ions dissolve in water

  The ionic lattice breaks down and the negative ions are surrounded by hydrogen and the positive ions are surrounded by oxygen.
• How does molecular polarity affect bond polarity of molecules with different shapes?

  
• Draw a Linear molecule?

  
• Draw a trigonal Planar molecule?

  
• Draw a distorted trigonal planar molecule?

  
• Draw a trigonal by-pyramidal molecule?

  
• Draw a distorted trigonal bi-pyramidal molecule?

  
• Draw a trigonal Planar molecule?

  
• Draw a tetrahedral shape molecule?

  
• Draw a pyramidal molecule?

  
• Draw a Non-linear molecule?

  
• Draw a octrahedral molecule?

  
• Draw a distorted octahedral molecule?

  
• Draw a square planar molecule?