Formulae for ionic compounds
4 marks · NormalThe table shows the ions present in four different ionic compounds. Complete the formula for each compound in the table below:
| Compound name | Ions | Formula |
|---|---|---|
| sodium sulfide | Na+, S2– | |
| zinc nitrate | Zn2+, NO3– | |
| aluminium sulfate | Al3+, SO4^2– | |
| ammonium phosphate | NH4+, PO4^3– |
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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Must show: Na2S, Zn(NO3)2, Al2(SO4)3, (NH4)3PO4
Common mistakes: missing or incorrect brackets; unbalanced charges
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Marking points
A1 · 1 mark · Sodium sulfide: correct formula Na2S
A2 · 1 mark · Zinc nitrate: correct formula Zn(NO3)2
A3 · 1 mark · Aluminium sulfate: correct formula Al2(SO4)3
A4 · 1 mark · Ammonium phosphate: correct formula (NH4)3PO4
Worked solution
| Compound name | Ions | Formula |
|---|---|---|
| sodium sulfide | Na+, S2– | Na2S |
| zinc nitrate | Zn2+, NO3– | Zn(NO3)2 |
| aluminium sulfate | Al3+, SO4^2– | Al2(SO4)3 |
| ammonium phosphate | NH4+, PO4^3– | (NH4)3PO4 |