Ionic bonding

• 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, aka lose 1 electron = +1, loses 2 electrons = +2)
• What happens to a non-metal when forming an ionic bond?

  Gains electron and becomes negatively charged, (size of the charge is the same as the number of electrons gained, aka gain 1 electron = -1, gains 2 electrons = -2)
• Why do metals and non-metals form ionic bonds?

  To get a full outer shell and therefore have the electronic structure of a Noble gas
• 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

  Sodium loses an electron whilst chlorine gains an electron

  
• What are the limitations of using dot and cross diagrams to represent ionic compounds?

  • Does not show how the ions are arranged in space
  • does not show the structure in 3D
• 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 2+ ion

  Oxygen gains the 2 electrons and forms a 2- ion
• 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.
• How can the structure of sodium chloride be represented. What are the limitations?

  Space fill model: shows relative sizes of ions and regular pattern but can only see outer layer

  Ball & stick model: shows all the ions, bonds aren't represented by lines, doesn’t show outer electrons

  
• What must the charges do when working out a formula of an ionic compound?

  Cancel out e.g. Na+ and Cl- is NaCl, Mg2+ and Clis MgCl2 as need 2 Clto cancel out the 2+ from Mg
• What are the properties of ionic compounds?

  • High melting points/ high boiling points
  • Can conduct when molten (melted so liquid) or when in solution (dissolved in water)
• Why do ionic compounds have high melting points?

  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 (can’t move when a solid) And carry a charge
• 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 empirical formula?

  Calcium is in group 2 so forms 2+ ion, chloride is in group 7 so forms 1- ion, need 2 chlorides to balance out the charge on the calcium = CaCl2