Key Concept: Ionic compounds are neutral overall. Balance positive and negative charges to write formulae.
Section A: Writing Formulae
1. Write the formula for sodium chloride. [1]
2. Write the formula for magnesium oxide. [1]
3. Write the formula for aluminium sulfate. [2]
4. Write the formula for calcium nitrate. [2]
5. Write the formula for ammonium carbonate. [2]
Section B: Charges
6. State the charge on each ion: Na, Mg, Al, O, Cl, SO4. [3]
Total marks: 11
Mark Scheme
1. NaCl [1]
2. MgO [1]
3. Al2(SO4)3 [2]
4. Ca(NO3)2 [2]
5. (NH4)2CO3 [2]
6. Na+, Mg2+, Al3+, O2-, Cl-, SO4 2- [3]