Bonding

• What is ionic bonding?


  oppositely charged ions held together by strong electrostatic forces of attraction
• How do ionic boonds form?

  the transfer of an electron from one atom to another
• What are the charges of these ionic compounds?


  OH -

  NO3 -

  NH4 +

  SO4 2-

  CO3 2-
• What is the structure of ionic compounds?

  giant ionic structure
• Can ionic compounds dissolve in water and why?

  do dissolve in water as water molecules are polar so can attract the charged ions
• Can ionic compound conduct?

  can conduct when molten or dissolved in solution as ions are free to move around and carry charge/kinetic energy
• Melting point of ionic compound?

  high melting point as many strong electrostatic forces of attraction between oppositely charged ions therefore lots of energy is needed to overcome these forces
• What is covalent bonding?


  the sharing of outer electrons in order for atoms to obtain a full shell
• What are dative covalent/coordinate bonds?


  when one atom donates a pair of electrons to another atoms
• What are two examples of giant covalent structure?


  Graphite and Diamond
• Properties of Graphite?


  Each carbon bonded to 3 others

  One delocalised electron per carbon, therefore is conductive as the electrons can carry charge

  High melting point as strong covalent bonds

  Layers slide past each other easily due to week IMF between them

  Insoluble as bonds are too strong
• Properties of Diamond?


  Each carbon is bonded to 4 others

  Rigid structure, hard

  High melting point as strong covalent bonds
• What repels more lone pairs or bonding pairs? and by what degrees?


  lone pairs

  lp-lp > lp-bp > bp-bp

  2.5 degrees
• What is electronegativity?


  the ability of an atom to pull the electron density in a covalent bond towards itself
• What is the most electronegative atom?


  Fluorine
• What causes a covalent bond to be polar?

  a difference in electronegativity between the atoms
• What stops polar bonds from having overall polarity?


  if they are arranged symmetrically
• What are the 3 types of IMF?


  Van der Waals

  Permanent Dipole-Dipole

  H+ bonding
• Arrange the IMF from weakest to strongest


  VdW < Dipole-dipole < H+ bonding
• How do VdW form?


  electrons in the molecule can move from one end to another leading to a temporary dipole, this effects electron distribution in nearby molecules leading to induced dipoles creating a force of attraction
• What makes VdW stronger?


  the bigger the molecule the more VdW as there is a larger cloud of electrons
• How does H+ bonding form?


  when the H on one molecule forms a bond with the lone pair on a N O F atom bonded to another H
• What structures do metallic bonds have


  Giant Metallic Lattice
• What causes metallic bonding?


  strong electrostatic forces of attraction between positive metal ions and 'sea' of delocalised electrons
• Melting point in metallic bonding

  more electrons an atom can donate the higher the melting point