Ionic formula writing practice worksheet with handwritten chemical formulas and ions.

It looks like you've uploaded a worksheet titled "Ionic Formula Writing Practice More", which asks students to write the formulas for various ionic compounds. Some answers are already filled in, but not all. I’ll help you solve the remaining problems step by step and explain how to write ionic compound formulas correctly.

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🔧 How to Write Ionic Formulas:

1. Identify the cation (positive ion) and anion (negative ion).
2. Determine their charges using periodic table trends or given oxidation states.
3. Balance the charges so the total positive charge equals the total negative charge.
4. Use subscripts to show the number of each ion needed.
5. Do not include charges in the final formula—only subscripts.

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Let’s go through each problem one by one:

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1) magnesium chloride

- Mg²⁺ + Cl⁻
- Need 2 Cl⁻ to balance 1 Mg²⁺ → MgCl₂

✔ Answer: MgCl₂

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2) lithium oxide

- Li⁺ + O²⁻
- Need 2 Li⁺ to balance 1 O²⁻ → Li₂O

✔ Answer: Li₂O

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3) magnesium hydroxide

- Mg²⁺ + OH⁻
- Need 2 OH⁻ to balance 1 Mg²⁺ → Mg(OH)₂

✔ Answer: Mg(OH)₂

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4) calcium bromide

- Ca²⁺ + Br⁻
- Need 2 Br⁻ → CaBr₂

✔ Answer: CaBr₂

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5) barium sulfate

- Ba²⁺ + SO₄²⁻
- Charges balance: 1:1 → BaSO₄

✔ Answer: BaSO₄

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6) sodium hydroxide

- Na⁺ + OH⁻ → NaOH

✔ Answer: NaOH

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7) beryllium hydroxide

- Be²⁺ + OH⁻
- Need 2 OH⁻ → Be(OH)₂

✔ Answer: Be(OH)₂

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8) zinc carbonate

- Zn²⁺ + CO₃²⁻ → ZnCO₃

✔ Answer: ZnCO₃

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9) manganese(II) arsenide

- Mn²⁺ + As³⁻
- LCM of 2 and 3 is 6 → need 3 Mn²⁺ and 2 As³⁻ → Mn₃As₂

✔ Answer: Mn₃As₂

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10) copper(II) chloride

- Cu²⁺ + Cl⁻
- Need 2 Cl⁻ → CuCl₂

✔ Answer: CuCl₂

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11) cobalt(II) chloride

- Co²⁺ + Cl⁻ → CoCl₂

✔ Answer: CoCl₂

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12) ammonium oxide

- NH₄⁺ + O²⁻
- Need 2 NH₄⁺ → (NH₄)₂O

✔ Answer: (NH₄)₂O

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13) potassium hydroxide

- K⁺ + OH⁻ → KOH

✔ Answer: KOH

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14) lead(IV) sulfide

- Pb⁴⁺ + S²⁻
- LCM of 4 and 2 is 4 → need 1 Pb⁴⁺ and 2 S²⁻ → PbS₂

✔ Answer: PbS₂

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15) silver cyanide

- Ag⁺ + CN⁻ → AgCN

✔ Answer: AgCN

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16) vanadium(V) nitrite

- V⁵⁺ + NO₂⁻
- Need 5 NO₂⁻ → V(NO₂)₅

✔ Answer: V(NO₂)₅

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17) aluminum arsenate

- Al³⁺ + AsO₄³⁻
- Charges balance 1:1 → AlAsO₄

✔ Answer: AlAsO₄

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18) magnesium acetate

- Mg²⁺ + C₂H₃O₂⁻
- Need 2 acetate ions → Mg(C₂H₃O₂)₂

✔ Answer: Mg(C₂H₃O₂)₂

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19) sodium (I) sulfate

- Na⁺ + SO₄²⁻
- Need 2 Na⁺ → Na₂SO₄

⚠️ Note: Sodium is always +1, so "sodium (I)" is redundant, but correct.

✔ Answer: Na₂SO₄

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20) ammonium sulfate

- NH₄⁺ + SO₄²⁻
- Need 2 NH₄⁺ → (NH₄)₂SO₄

✔ Answer: (NH₄)₂SO₄

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✔ Final Answers Summary:

| # | Compound | Formula |
|---|---------------------------|------------------------|
| 1 | magnesium chloride | MgCl₂ |
| 2 | lithium oxide | Li₂O |
| 3 | magnesium hydroxide | Mg(OH)₂ |
| 4 | calcium bromide | CaBr₂ |
| 5 | barium sulfate | BaSO₄ |
| 6 | sodium hydroxide | NaOH |
| 7 | beryllium hydroxide | Be(OH)₂ |
| 8 | zinc carbonate | ZnCO₃ |
| 9 | manganese(II) arsenide | Mn₃As₂ |
|10 | copper(II) chloride | CuCl₂ |
|11 | cobalt(II) chloride | CoCl₂ |
|12 | ammonium oxide | (NH₄)₂O |
|13 | potassium hydroxide | KOH |
|14 | lead(IV) sulfide | PbS₂ |
|15 | silver cyanide | AgCN |
|16 | vanadium(V) nitrite | V(NO₂)₅ |
|17 | aluminum arsenate | AlAsO₄ |
|18 | magnesium acetate | Mg(C₂H₃O₂)₂ |
|19 | sodium sulfate | Na₂SO₄ |
|20 | ammonium sulfate | (NH₄)₂SO₄ |

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📝 Notes:

- Polyatomic ions must be enclosed in parentheses when more than one is used (e.g., (OH)₂, (NO₂)₅).
- Always balance charges to make the compound neutral.
- Transition metals with Roman numerals indicate variable charges — use that to determine the cation charge.

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