Hydrogen bromide is a compound of the two elements hydrogen and bromine. It melts at $-87 °\mathrm{C}$ and boils at $-67 °\mathrm{C}$. Draw a diagram of the bonding between the atoms, showing only the outer electrons. 

• Cotton being woven to make sheets.

Is it a chemical change or a physical change? Give reason.

Aluminium and nitrogen react to form an ionic compound called aluminium nitride.

Name another non-metal that will form an ionic compound with aluminium, in the same way as nitrogen does.

The compound zinc sulphide has a structure like this:

Which does the diagram represent: a giant structure, or a molecular structure? 

The compound zinc sulphide has a structure like this:

Which type of bonding does zinc sulphide have? 

The compound zinc sulphide has a structure like this:

Look carefully at the structure. How many: 
i) sulphur ions are joined to each zinc ion? 
ii) zinc ions are joined to each sulphur ion? 
 

The compound zinc sulphide has a structure like this:

i) Deduce the formula of zinc sulphide. 

ii) Is this formula consistent with the charges on the two ions? Explain your answer.