Worksheet for practicing naming and writing formulas of ionic compounds with polyatomic ions.

Here is the completed table with explanations for each ionic compound containing polyatomic ions.

---

✔ How to Name and Write Formulas for Ionic Compounds with Polyatomic Ions:

1. Identify the cation (positive ion) and anion (negative ion).
2. Know the charge of each ion — monatomic ions follow periodic table trends; polyatomic ions have fixed charges you must memorize (e.g., NO₃⁻, SO₄²⁻, PO₄³⁻, NH₄⁺, etc.).
3. Balance the total positive and negative charges to make a neutral compound.
4. Use parentheses around polyatomic ions if more than one is needed.
5. Name the cation first, then the anion.

---

## 🔢 Completed Table:

| # | Name of Ionic Compound | Formula of Ionic Compound |
|---|--------------------------------|---------------------------|
| 1 | Sodium chromate | Na₂CrO₄ |
| 2 | Calcium carbonate | CaCO₃ |
| 3 | Magnesium nitrate | Mg(NO₃)₂ |
| 4 | Aluminum sulfate | Al₂(SO₄)₃ |
| 5 | Lithium phosphate | Li₃PO₄ |
| 6 | Ammonium chloride | NH₄Cl |
| 7 | Cesium chlorate | CsClO₃ |
| 8 | Potassium sulfate | K₂SO₄ |
| 9 | Barium acetate | Ba(C₂H₃O₂)₂ |
|10 | Rubidium cyanide | RbCN |
|11 | Potassium acetate | KCH₃CO₂ |
|12 | Magnesium phosphate | Mg₃(PO₄)₂ |
|13 | Aluminum chlorate | Al(ClO₃)₃ |
|14 | Calcium sulfate | CaSO₄ |
|15 | Strontium bicarbonate | Sr(HCO₃)₂ |
|16 | Sodium nitrate | NaNO₃ |
|17 | Lithium carbonate | Li₂CO₃ |
|18 | Barium nitrate | Ba(NO₃)₂ |
|19 | Cesium chromate | Cs₂CrO₄ |
|20 | Ammonium hydroxide | NH₄OH |

---

## 📘 Detailed Explanations:

1. Sodium chromate → Na₂CrO₄

- Sodium (Na⁺), Chromate (CrO₄²⁻)
- Need 2 Na⁺ to balance 1 CrO₄²⁻ → Na₂CrO₄

2. Calcium carbonate → CaCO₃

- Ca²⁺ and CO₃²⁻ → charges cancel directly → CaCO₃

3. Magnesium nitrate → Mg(NO₃)₂

- Mg²⁺ and NO₃⁻ → need two nitrates → Mg(NO₃)₂

4. Aluminum sulfate → Al₂(SO₄)₃

- Al³⁺ and SO₄²⁻ → LCM of 3 and 2 is 6 → 2 Al³⁺ = +6, 3 SO₄²⁻ = -6 → Al₂(SO₄)₃

5. Lithium phosphate → Li₃PO₄

- Li⁺ and PO₄³⁻ → need 3 Li⁺ → Li₃PO₄

6. Ammonium chloride → NH₄Cl

- NH₄⁺ and Cl⁻ → 1:1 ratio → NH₄Cl

7. Cesium chlorate → CsClO₃

- Cs⁺ and ClO₃⁻ → 1:1 → CsClO₃

8. Potassium sulfate → K₂SO₄

- K⁺ and SO₄²⁻ → need 2 K⁺ → K₂SO₄

9. Barium acetate → Ba(C₂H₃O₂)₂

- Ba²⁺ and C₂H₃O₂⁻ → need 2 acetates → Ba(C₂H₃O₂)₂
*(Note: Acetate is often written as CH₃COO⁻ or C₂H₃O₂⁻)*

10. Rubidium cyanide → RbCN

- Rb⁺ and CN⁻ → 1:1 → RbCN

---

Reverse: From Formula to Name

#### 11. KCH₃CO₂ → Potassium acetate
- K⁺ and CH₃COO⁻ → potassium acetate

#### 12. Mg₃(PO₄)₂ → Magnesium phosphate
- Mg²⁺ and PO₄³⁻ → magnesium phosphate

#### 13. Al(ClO₃)₃ → Aluminum chlorate
- Al³⁺ and ClO₃⁻ → aluminum chlorate

#### 14. CaSO₄ → Calcium sulfate
- Ca²⁺ and SO₄²⁻ → calcium sulfate

#### 15. Sr(HCO₃)₂ → Strontium bicarbonate
- Sr²⁺ and HCO₃⁻ → strontium bicarbonate *(also called hydrogen carbonate)*

#### 16. NaNO₃ → Sodium nitrate
- Na⁺ and NO₃⁻ → sodium nitrate

#### 17. Li₂CO₃ → Lithium carbonate
- Li⁺ and CO₃²⁻ → lithium carbonate

#### 18. Ba(NO₃)₂ → Barium nitrate
- Ba²⁺ and NO₃⁻ → barium nitrate

#### 19. Cs₂CrO₄ → Cesium chromate
- Cs⁺ and CrO₄²⁻ → cesium chromate

#### 20. NH₄OH → Ammonium hydroxide
- NH₄⁺ and OH⁻ → ammonium hydroxide

---

## 📌 Important Notes:
- Polyatomic ions to memorize:
- Nitrate: NO₃⁻
- Sulfate: SO₄²⁻
- Phosphate: PO₄³⁻
- Carbonate: CO₃²⁻
- Acetate: C₂H₃O₂⁻
- Ammonium: NH₄⁺
- Hydroxide: OH⁻
- Chlorate: ClO₃⁻
- Chromate: CrO₄²⁻
- Bicarbonate: HCO₃⁻
- Cyanide: CN⁻

- Always use parentheses when more than one polyatomic ion is needed (e.g., Mg(NO₃)₂, not MgNO₃₂).

---

✔ Your worksheet is now fully completed with correct formulas and names!

Let me know if you’d like flashcards or a quiz to practice these!