Mr. Brueckners Chemistry Class - HHS - 2011-12: Key for Word ... - Free Printable

You're working on ionic bonding — specifically, showing how electrons are transferred from metals to nonmetals to form stable ions and ionic compounds.

Let’s go step by step for each combination. The goal is to draw Lewis dot diagrams showing the transfer of electrons, just like the examples given (Na → Cl and Ca → Cl₂).

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🔑 Key Concepts:

- Metals (left side of periodic table) lose electrons to form cations (+ charge).
- Nonmetals (right side) gain electrons to form anions (– charge).
- Atoms want full outer shells (octet rule, except H/He which want 2).
- Use Lewis dot structures: dots represent valence electrons.
- Show arrows indicating electron transfer.
- Write the resulting ionic compound formula.

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## ✔ Problem Solutions:

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1. K + F

- Potassium (K): Group 1 → 1 valence electron → loses 1 e⁻ → becomes K⁺
- Fluorine (F): Group 17 → 7 valence electrons → gains 1 e⁻ → becomes F⁻

➡️ Transfer: 1 electron from K to F
➡️ Compound: KF

Lewis Diagram:

```
• ••
K• + •F•• → K⁺ [••F••]⁻
•• ••
```

*(Draw arrow from K’s dot to F)*

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2. Mg + I

- Magnesium (Mg): Group 2 → 2 valence electrons → loses 2 e⁻ → Mg²⁺
- Iodine (I): Group 17 → 7 valence electrons → needs 1 e⁻ per atom → so we need 2 I atoms

➡️ Transfer: Mg gives 1 electron to each of two I atoms
➡️ Compound: MgI₂

Lewis Diagram:

```
•• •• ••
•Mg• + 2 × •I•• → Mg²⁺ [••I••]⁻ [••I••]⁻
•• •• ••
```

*(Draw 2 arrows from Mg to each I)*

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3. Be + S

- Beryllium (Be): Group 2 → 2 valence electrons → Be²⁺
- Sulfur (S): Group 16 → 6 valence electrons → needs 2 e⁻ → S²⁻

➡️ Transfer: Be gives both electrons to S
➡️ Compound: BeS

Lewis Diagram:

```
• ••
•Be• + •S•• → Be²⁺ [••S••]²⁻
• ••
```

*(Draw 2 arrows from Be to S)*

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4. Na + O

- Sodium (Na): Group 1 → 1 valence electron → Na⁺
- Oxygen (O): Group 16 → 6 valence electrons → needs 2 e⁻ → so we need 2 Na atoms

➡️ Transfer: Each Na gives 1 e⁻ to O → total 2 e⁻ transferred
➡️ Compound: Na₂O

Lewis Diagram:

```
• •• ••
2 × Na• + •O•• → 2 × Na⁺ [••O••]²⁻
•• ••
```

*(Draw 2 arrows from each Na to O)*

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5. Al + Br

- Aluminum (Al): Group 13 → 3 valence electrons → Al³⁺
- Bromine (Br): Group 17 → 7 valence electrons → needs 1 e⁻ per atom → so we need 3 Br atoms

➡️ Transfer: Al gives 1 e⁻ to each of three Br atoms
➡️ Compound: AlBr₃

Lewis Diagram:

```
•• •• •• ••
•Al• + 3 × •Br•• → Al³⁺ [••Br••]⁻ [••Br••]⁻ [••Br••]⁻
•• •• •• ••
```

*(Draw 3 arrows from Al to each Br)*

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## 📝 Final Tips for Drawing:

- Always show valence electrons as dots around the element symbol.
- Use arrows to show direction of electron transfer (metal → nonmetal).
- After transfer, show ions with charges.
- Make sure the total electrons lost = total gained.
- Write the correct chemical formula based on ion charges.

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✔ You’ve now completed all 5 problems! Just draw them neatly using Lewis structures and arrows as shown above.

Let me know if you’d like printable versions or hand-drawn sketches!