Bonding

• name three types of chemical bonds

  ionic, covalent & metallic
• what are the particles like in an ionic bond

  oppositely charged ions
• what do atoms do in a covalent bond to get a full outer shell

  share pairs of electrons
• what particles are involved in metallic bonding

  positive ions and delocalised electrons
• what type of bond is formed between a metal and non-metals

  ionic
• what type of bonding is formed between just non-metals

  covalent
• what type of bonding occurs in metals and alloys

  metallic
• what type of bond involves gain or loss of electrons

  ionic
• what happens when a metal and a non-metal from an ionic bond

  electrons in the outer shell of the metal atom are transferred to the non-metal
• What is the group number if an element forms a -2 ion

  6
• If an atom loses two electrons to form an ion, what charge will the ion have

  +2
• what happens to a metal when forming an ionic bond

  loses electrons and becomes positively charged, size of charge is the same as the number of electrons lost
• what happens to a non-metal when forming an ionic bond

  gain electrons and become negatively charged, size of the charge is the same as the number of electrons gained
• how can the transfer of electrons when forming an ionic bond be represented

  dot and cross diagrams
• Draw the dot and cross diagram for the formation of sodium chloride

  
• what type of bonding is likely to occur between group 1&2 metals with group 6&7 non-metals

  ionic
• Describe how magnesium and oxygen form an ionic bond

  Magnesium loses 2 electrons and forms a positive ion. Oxygen gains the 2 electrons and form a negative ion to get a full outer shell
• what type of force exists between oppositely charged ions

  electrostatic
• what type of structure is found in ionic compounds

  giant lattice
• Describe the bonding and structure in an ionic compound

  • Giant lattice
  • strong electrostatic attraction between oppositely charged ions with the forces acting in all directions.
  • Ionic bonds are strong
• How can the structure of sodium chloride be represented

  ball & stick model shows all the ions, relative sizes of ions aren't shown
• what must the charges do when working out a formula of an ionic compound

  Balance

  e.g. Na+ and Cl- is NaCl, Mg2+ and Cl- is MgCl2
• what are the properties of ionic compounds

  • high melting points
  • high boiling points
  • Can conduct electricity when molten or when in solution
• why do ionic compounds have high melting points

  ionic bonds are strong due to the strong electrostatic attraction between oppositely charged ions which requires lots of energy to break
• why do ionic compounds conduct when melted or dissolved in water

  ions are free to move (cant move when a solid!)
• How do you work out the empirical formula of an ionic compounds from a diagram

  work out the charges on the ions and balance them out e.g. K is in group 1 so 1+, O is in group 6 so 2+, so formula is K2O
• a compound is made up of calcium ions and chloride ions, what is its emprirical formula

  calcium is in group 2 so form 2+ ion, chloride is in grouo 7 so forms 1- ion, need 2 chlrorides to balance out the charge on the calcium, is CaCl2
• how are covalent bonds formed

  by sharing electrons
• How many electrons does each atom donate in a single covalent bond

  1
• what is the strength of a covalent bond

  strong
• what are the limitations of using a displayed formula

  • Does not show 3D structure
  • Does not show where the electrons in the covalent bond have come from
• what type of bonding to you get in polymers (large molecules)

  covalent
• how are the atoms linked in a polymer

  by strong covalent bonds between the atoms with weak intermolecular forces between the polymer chains
• what are the properties of small covalent molecules

  • Usually gases or liquids
  • low melting points and boiling points
  • do not conduct electricity
• why do small covalent molecules have low boiling points (gases and evaporate easily)

  they have weak intermolecular forces which are easily broken
• what happens to the boiling point of simple covalent molecules with increasing size

  increases and the strength of the weak intermolecular forces increases
• which has the highest boiling point out of hydrogen and methane

  methane as it is a larger molecule so the intermolecular forces are stronger as strength of the intermolecular forces is dictated by size of the molecule
• why don't simple covalent molecules conduct electricity

  have no overall electrical charge, no free moving charged particles (ions or electrons) able to carry the current
• name three giant covalent structure

  diamond, graphite and silicon dioxide (silica)
• what are the melting point of giant covalent structures

  high