Worksheet for writing neutral formulas of ionic compounds, featuring a table with compound names, cations, anions, and formulas.

Absolutely! Let’s solve this worksheet step by step. The goal is to write the neutral ionic formula for each compound by identifying the correct cation (positive ion) and anion (negative ion), then balancing their charges so the total charge equals zero.

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🔑 Key Rules:

- Use the periodic table to find common ionic charges.
- Group 1: +1 (e.g., Na⁺, K⁺)
- Group 2: +2 (e.g., Ca²⁺, Mg²⁺)
- Group 3: +3 (e.g., Al³⁺)
- Group 5: -3 (e.g., N³⁻)
- Group 6: -2 (e.g., O²⁻, S²⁻)
- Group 7: -1 (e.g., F⁻, Cl⁻)
- Transition metals: Charge given in Roman numerals (e.g., Copper (II) = Cu²⁺, Iron (III) = Fe³⁺)

To write a neutral formula:
> Find the least common multiple of the charges, then use subscripts to balance.

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## ✔ Let’s fill out the table:

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#3: Aluminum chloride

- Aluminum (Al) is in Group 3 → Al³⁺
- Chlorine (Cl) is in Group 7 → Cl⁻
- To balance: 3+ needs 3×(-1) → need 3 Cl⁻
- Formula: AlCl₃

✔ Cation: Al³⁺
✔ Anion: Cl⁻
✔ Neutral Formula: AlCl₃

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#4: Aluminum oxide

- Aluminum: Al³⁺
- Oxygen: Group 6 → O²⁻
- LCM of 3 and 2 is 6 → need 2 Al³⁺ (total +6) and 3 O²⁻ (total -6)
- Formula: Al₂O₃

✔ Cation: Al³⁺
✔ Anion: O²⁻
✔ Neutral Formula: Al₂O₃

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#5: Beryllium fluoride

- Beryllium (Be): Group 2 → Be²⁺
- Fluorine (F): Group 7 → F⁻
- Need 2 F⁻ to balance Be²⁺
- Formula: BeF₂

✔ Cation: Be²⁺
✔ Anion: F⁻
✔ Neutral Formula: BeF₂

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#6: Sodium oxide

- Sodium (Na): Group 1 → Na⁺
- Oxygen: O²⁻
- Need 2 Na⁺ to balance O²⁻
- Formula: Na₂O

✔ Cation: Na⁺
✔ Anion: O²⁻
✔ Neutral Formula: Na₂O

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#7: Copper (II) sulfide

- Copper (II) → Cu²⁺
- Sulfur (S): Group 6 → S²⁻
- Charges already balance: +2 and -2 → 1:1 ratio
- Formula: CuS

✔ Cation: Cu²⁺
✔ Anion: S²⁻
✔ Neutral Formula: CuS

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#8: Aluminum fluoride

- Aluminum: Al³⁺
- Fluorine: F⁻
- Need 3 F⁻ to balance Al³⁺
- Formula: AlF₃

✔ Cation: Al³⁺
✔ Anion: F⁻
✔ Neutral Formula: AlF₃

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#9: Manganese (III) oxide

- Manganese (III) → Mn³⁺
- Oxygen: O²⁻
- LCM of 3 and 2 is 6 → need 2 Mn³⁺ (+6) and 3 O²⁻ (-6)
- Formula: Mn₂O₃

✔ Cation: Mn³⁺
✔ Anion: O²⁻
✔ Neutral Formula: Mn₂O₃

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#10: Magnesium nitride

- Magnesium (Mg): Group 2 → Mg²⁺
- Nitrogen (N): Group 5 → N³⁻
- LCM of 2 and 3 is 6 → need 3 Mg²⁺ (+6) and 2 N³⁻ (-6)
- Formula: Mg₃N₂

✔ Cation: Mg²⁺
✔ Anion: N³⁻
✔ Neutral Formula: Mg₃N₂

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#11: Sodium sulfide

- Sodium: Na⁺
- Sulfur: S²⁻
- Need 2 Na⁺ to balance S²⁻
- Formula: Na₂S

✔ Cation: Na⁺
✔ Anion: S²⁻
✔ Neutral Formula: Na₂S

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#12: Iron (III) oxide

- Iron (III) → Fe³⁺
- Oxygen: O²⁻
- LCM of 3 and 2 is 6 → need 2 Fe³⁺ (+6) and 3 O²⁻ (-6)
- Formula: Fe₂O₃

✔ Cation: Fe³⁺
✔ Anion: O²⁻
✔ Neutral Formula: Fe₂O₃

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## 📋 Final Completed Table:

| # | Compound Name | Cation | Anion | Neutral Ionic Formula |
|----|------------------------|-----------|-----------|------------------------|
| 1 | Sodium chloride | Na⁺ | Cl⁻ | NaCl |
| 2 | Calcium fluoride | Ca²⁺ | F⁻ | CaF₂ |
| 3 | Aluminum chloride | Al³⁺ | Cl⁻ | AlCl₃ |
| 4 | Aluminum oxide | Al³⁺ | O²⁻ | Al₂O₃ |
| 5 | Beryllium fluoride | Be²⁺ | F⁻ | BeF₂ |
| 6 | Sodium oxide | Na⁺ | O²⁻ | Na₂O |
| 7 | Copper (II) sulfide | Cu²⁺ | S²⁻ | CuS |
| 8 | Aluminum fluoride | Al³⁺ | F⁻ | AlF₃ |
| 9 | Manganese (III) oxide | Mn³⁺ | O²⁻ | Mn₂O₃ |
| 10 | Magnesium nitride | Mg²⁺ | N³⁻ | Mg₃N₂ |
| 11 | Sodium sulfide | Na⁺ | S²⁻ | Na₂S |
| 12 | Iron (III) oxide | Fe³⁺ | O²⁻ | Fe₂O₃ |

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## 💡 Summary:
You’re essentially playing “charge balancing” — make sure the total positive charge equals the total negative charge. Use subscripts to indicate how many ions you need. Always reduce subscripts if possible (but in these cases, they’re already in lowest terms).

Let me know if you’d like a printable version or flashcards for practice! 😊