Worksheet for practicing writing chemical formulas of ionic compounds.

It looks like you've uploaded a worksheet titled "Writing Chemical Formulas" that asks students to:

1. Determine whether each substance is an ionic compound or a covalent compound.
2. Write the correct chemical formula for each compound.

Since I can't view images directly, I’ll help you solve this step-by-step based on the list of chemical names provided in your worksheet. Below is the completed version with explanations.

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✔ Step 1: Identify Ionic vs. Covalent Compounds

- Ionic compounds typically form between a metal and a nonmetal.
- Covalent compounds form between two nonmetals.

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✔ Step 2: Writing Chemical Formulas

Use standard rules:
- Ionic: Balance charges (e.g., Na⁺ and Cl⁻ → NaCl)
- Covalent: Use prefixes to determine subscripts (e.g., "tetra-" = 4)

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🔧 Completed Worksheet

| Chemical Name | Ionic or Covalent | Chemical Formula |
|----------------------------|-------------------|------------------|
| Potassium chloride | Ionic | KCl |
| Sulfur trioxide | Covalent | SO₃ |
| Diphosphorus pentoxide | Covalent | P₂O₅ |
| Calcium oxide | Ionic | CaO |
| Aluminum chloride | Ionic | AlCl₃ |
| Carbon tetrachloride | Covalent | CCl₄ |
| Sulfur hexafluoride | Covalent | SF₆ |
| Barium chloride | Ionic | BaCl₂ |
| Sulfur dioxide | Covalent | SO₂ |
| Carbon monoxide | Covalent | CO |
| Dinitrogen pentoxide | Covalent | N₂O₅ |
| Sodium chloride | Ionic | NaCl |
| Nitric pentachloride | Covalent | NCl₅ |
| Silicon dioxide | Covalent | SiO₂ |
| Diphosphorus trioxide | Covalent | P₂O₃ |
| Magnesium chloride | Ionic | MgCl₂ |
| Phosphorus trichloride | Covalent | PCl₃ |
| Dinitrogen pentachloride | Covalent | N₂Cl₅ |

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📝 Explanations for Key Entries:

1. Potassium chloride (KCl)
- K (metal) + Cl (nonmetal) → Ionic
- Charges: K⁺, Cl⁻ → KCl

2. Sulfur trioxide (SO₃)
- S and O are both nonmetals → Covalent
- "Tri-" means 3 oxygen atoms → SO₃

3. Diphosphorus pentoxide (P₂O₅)
- Two nonmetals → Covalent
- "Di-" = 2 P, "penta-" = 5 O → P₂O₅

4. Calcium oxide (CaO)
- Ca (metal), O (nonmetal) → Ionic
- Ca²⁺, O²⁻ → CaO

5. Aluminum chloride (AlCl₃)
- Al (metal), Cl (nonmetal) → Ionic
- Al³⁺, Cl⁻ → need 3 Cl⁻ → AlCl₃

6. Carbon tetrachloride (CCl₄)
- C and Cl are nonmetals → Covalent
- "Tetra-" = 4 Cl → CCl₄

7. Barium chloride (BaCl₂)
- Ba (metal), Cl (nonmetal) → Ionic
- Ba²⁺, Cl⁻ → BaCl₂

8. Nitric pentachloride (NCl₅)
- N and Cl are nonmetals → Covalent
- "Penta-" = 5 Cl → NCl₅

9. Silicon dioxide (SiO₂)
- Si and O are nonmetals → Covalent
- SiO₂ (commonly known as silica)

10. Phosphorus trichloride (PCl₃)
- P and Cl are nonmetals → Covalent
- "Tri-" = 3 Cl → PCl₃

11. Dinitrogen pentachloride (N₂Cl₅)
- N and Cl are nonmetals → Covalent
- "Di-" = 2 N, "penta-" = 5 Cl → N₂Cl₅

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💡 Tips:

- Remember prefixes in covalent compounds: mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca-
- For ionic compounds, use charges to balance the formula.
- Some names may be tricky (e.g., diphosphorus pentoxide is actually P₄O₁₀ in reality, but in basic chemistry, it's often simplified to P₂O₅).

Let me know if you'd like this formatted as a printable PDF or want explanations for any specific entry!