1.37 draw a diagram to represent the positions of the ions in a crystal of sodium chloride.

Ionic Compounds

Like this with positive ions touching negative ions and vice versa. 

1.36 describe an ionic crystal as a giant three-dimensional lattice structure held together by the attraction between oppositely charged ions

Ionic Compounds

In an ionic crystal all the positively charged ions attract the negatively charged ions and arrange themselves into a giant 3D lattice. 

e.g. Sodium Chloride

1.35 understand the relationship between ionic charge and the melting point and boiling point of an ionic compound

Ionic Compounds

We know that ionic compounds are two ions which are attracted by electrostatic forces. This is because like forces attract. If the charges are increased and each ions have a greater charge then they will have greater electrostatic forces. This means more energy is required to break them so they have a higher melting/boiling point. 

e.g

Mg²⁺O²⁺ has a higher melting point than Na⁺Cl^-