Worksheet for practicing naming ionic compounds with examples and answers.

Let’s go through each compound name and write the correct chemical formula step by step. We’ll use what we know about ions and how they combine to make neutral compounds.

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1. Iron(II) chloride
- Iron(II) means Fe²⁺
- Chloride is Cl⁻
- To balance: need 2 Cl⁻ for every Fe²⁺ → FeCl₂

2. Sodium sulfate
- Sodium is Na⁺
- Sulfate is SO₄²⁻
- Need 2 Na⁺ to balance one SO₄²⁻ → Na₂SO₄

3. Silver nitrate
- Silver is Ag⁺ (always +1 in common compounds)
- Nitrate is NO₃⁻
- They combine 1:1 → AgNO₃

4. Potassium oxide
- Potassium is K⁺
- Oxide is O²⁻
- Need 2 K⁺ to balance O²⁻ → K₂O

5. Zinc carbonate
- Zinc is Zn²⁺
- Carbonate is CO₃²⁻
- Charges cancel → ZnCO₃

6. Calcium hydroxide
- Calcium is Ca²⁺
- Hydroxide is OH⁻
- Need 2 OH⁻ to balance Ca²⁺ → Ca(OH)₂

7. Aluminum sulfide
- Aluminum is Al³⁺
- Sulfide is S²⁻
- Find least common multiple of charges: 6
→ 2 Al³⁺ = +6, 3 S²⁻ = -6 → Al₂S₃

8. Magnesium phosphate
- Magnesium is Mg²⁺
- Phosphate is PO₄³⁻
- LCM of 2 and 3 is 6
→ 3 Mg²⁺ = +6, 2 PO₄³⁻ = -6 → Mg₃(PO₄)₂

9. Copper(I) bromide
- Copper(I) means Cu⁺
- Bromide is Br⁻
- Combine 1:1 → CuBr

10. Lead(IV) oxide
- Lead(IV) means Pb⁴⁺
- Oxide is O²⁻
- Need 2 O²⁻ to balance Pb⁴⁺ → PbO₂

11. Ammonium chloride
- Ammonium is NH₄⁺
- Chloride is Cl⁻
- Combine 1:1 → NH₄Cl

12. Lithium fluoride
- Lithium is Li⁺
- Fluoride is F⁻
- Combine 1:1 → LiF

13. Barium iodide
- Barium is Ba²⁺
- Iodide is I⁻
- Need 2 I⁻ to balance Ba²⁺ → BaI₂

14. Cobalt(III) sulfate
- Cobalt(III) means Co³⁺
- Sulfate is SO₄²⁻
- LCM of 3 and 2 is 6
→ 2 Co³⁺ = +6, 3 SO₄²⁻ = -6 → Co₂(SO₄)₃

15. Tin(II) acetate
- Tin(II) means Sn²⁺
- Acetate is C₂H₃O₂⁻ (or CH₃COO)
- Need 2 acetates to balance Sn²⁺ → Sn(C₂H₃O₂)₂

16. Nickel(II) cyanide
- Nickel(II) means Ni²⁺
- Cyanide is CN⁻
- Need 2 CN⁻ to balance Ni²⁺ → Ni(CN)₂

17. Mercury(I) chloride
- Mercury(I) is special — it exists as Hg₂²⁺ (two mercury atoms bonded together with +2 charge total)
- Chloride is Cl⁻
- So we need 2 Cl⁻ to balance Hg₂²⁺ → Hg₂Cl₂

18. Chromium(III) oxide
- Chromium(III) means Cr³⁺
- Oxide is O²⁻
- LCM of 3 and 2 is 6
→ 2 Cr³⁺ = +6, 3 O²⁻ = -6 → Cr₂O₃

19. Manganese(II) permanganate
- Manganese(II) means Mn²⁺
- Permanganate is MnO₄⁻
- Need 2 permanganate ions to balance Mn²⁺ → Mn(MnO₄)₂
*(Note: This looks odd because both have “manganese”, but it’s correct — one is Mn²⁺ ion, the other is MnO₄⁻ polyatomic ion)*

20. Strontium phosphide
- Strontium is Sr²⁺
- Phosphide is P³⁻
- LCM of 2 and 3 is 6
→ 3 Sr²⁺ = +6, 2 P³⁻ = -6 → Sr₃P₂

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Final Answer:
1. FeCl₂
2. Na₂SO₄
3. AgNO₃
4. K₂O
5. ZnCO₃
6. Ca(OH)₂
7. Al₂S₃
8. Mg₃(PO₄)₂
9. CuBr
10. PbO₂
11. NH₄Cl
12. LiF
13. BaI₂
14. Co₂(SO₄)
15. Sn(C₂H₃O₂)₂
16. Ni(CN)₂
17. Hg₂Cl₂
18. Cr₂O₃
19. Mn(MnO₄)₂
20. Sr₃P₂