Chemistry worksheet asking students to draw dot diagrams for various ionic compounds.

Let’s go step by step to draw the dot diagrams (also called Lewis structures) for each compound.

Dot diagrams show how atoms share or transfer electrons to form bonds. For ionic compounds (metal + nonmetal), we show ions with charges and brackets. For covalent compounds (nonmetal + nonmetal), we show shared electron pairs as lines or dots between atoms.

We’ll use the example given: NaCl → Na⁺ and Cl⁻ (with 8 dots around Cl, in brackets, and charge shown).

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1. Li₂O

- Lithium (Li) is a metal (Group 1) → loses 1 electron → becomes Li⁺
- Oxygen (O) is a nonmetal (Group 16) → gains 2 electrons → becomes O²⁻
- So we need two Li⁺ to balance one O²⁻

Dot diagram:
[Li]⁺ [ :Ö: ]²⁻ [Li]⁺
(Each Li has no dots — it lost its valence electron. Oxygen has 8 dots — full octet — and 2– charge.)

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2. CaO

- Calcium (Ca) is Group 2 → loses 2 electrons → Ca²⁺
- Oxygen (O) gains 2 electrons → O²⁻

Dot diagram:
[Ca]²⁺ [ :Ö: ]²⁻

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3. AlN

- Aluminum (Al) is Group 13 → loses 3 electrons → Al³⁺
- Nitrogen (N) is Group 15 → gains 3 electrons → N³⁻

Dot diagram:
[Al]³⁺ [ :Ṇ: ]³⁻
(Nitrogen has 8 dots — 3 lone pairs + 1 bonding pair? Wait — actually, since it’s ionic, nitrogen gets 3 extra electrons → total 8 valence electrons → 4 pairs → so 8 dots around N)

Actually, correct: N³⁻ has 8 dots (full octet). Al³⁺ has no dots.

So: [Al]³⁺ [ :Ṇ: ]³⁻

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4. MgS

- Magnesium (Mg) Group 2 → Mg²⁺
- Sulfur (S) Group 16 → S²⁻

Dot diagram:
[Mg]²⁺ [ :S̈: ]²⁻
(Sulfur has 8 dots — 4 pairs)

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5. FeCl₃

Iron can have multiple charges, but here it’s Fe³⁺ because there are 3 Cl⁻ ions.

- Iron (Fe) → Fe³⁺ (loses 3 electrons)
- Each Chlorine (Cl) → Cl⁻ (gains 1 electron)

Dot diagram:
[Fe]³⁺ [ :Cl: ]⁻ [ :Cl: ]⁻ [ :Cl: ]⁻
(each Cl has 8 dots — 3 lone pairs + 1 bond? No — in ionic, just show Cl⁻ with 8 dots and charge)

Actually, better to write:

[Fe]³⁺ and three separate [ :Cl: ]⁻ ions

But since it’s one formula unit, we can write:

[Fe]³⁺ [ :Cl: ]⁻ [ :Cl: ]⁻ [ :Cl: ]⁻

Each Cl has 8 dots (4 pairs).

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6. CaF₂

- Calcium → Ca²⁺
- Each Fluorine → F⁻ (needs 1 electron each; two fluorines take 2 electrons from Ca)

Dot diagram:
[Ca]²⁺ [ :F: ]⁻ [ :F: ]⁻
(each F has 8 dots — 4 pairs)

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7. Ag₃P

Silver usually forms Ag⁺ (even though it’s transition metal, common ion is +1)

Phosphorus (P) is Group 15 → gains 3 electrons → P³⁻

So 3 Ag⁺ balance 1 P³⁻

Dot diagram:
[Ag]⁺ [Ag]⁺ [Ag]⁺ [ :Ṗ: ]³⁻
(P has 8 dots — 4 pairs)

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8. Ba₃N₂

Barium (Ba) Group 2 → Ba²⁺
Nitrogen (N) Group 15 → N³⁻

To balance: 3 Ba²⁺ = +6 charge, 2 N³⁻ = -6 charge → balanced

Dot diagram:
[Ba]²⁺ [Ba]²⁺ [Ba]²⁺ [ :: ]³⁻ [ :Ṇ: ]³⁻
(each N has 8 dots)

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9. Al₂O₃

Aluminum → Al³⁺
Oxygen → O²⁻

Balance: 2 Al³⁺ = +6, 3 O²⁻ = -6

Dot diagram:
[Al]³⁺ [Al]³⁺ [ :Ö: ]²⁻ [ :Ö: ]²⁻ [ :Ö: ]²⁻
(each O has 8 dots)

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10. ZnI₂

Zinc commonly forms Zn²⁺
Iodine (I) → I⁻

So: Zn²⁺ and two I⁻

Dot diagram:
[Zn]²⁺ [ :İ: ]⁻ [ :İ: ]⁻
(each I has 8 dots — 4 pairs)

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11. Au₂S₃

Gold can be Au³⁺ (common in sulfides)
Sulfur → S²⁻

Check: 2 Au³⁺ = +6, 3 S²⁻ = -6 → balanced

Dot diagram:
[Au]³⁺ [Au]³⁺ [ :S̈: ]²⁻ [ :S̈: ]²⁻ [ :S̈: ]²⁻
(each S has 8 dots)

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Now let’s compile all answers clearly.

Final Answer:

1. Li₂O: [Li]⁺ [Li]⁺ [ :Ö: ]²⁻
2. CaO: [Ca]²⁺ [ :Ö: ]²⁻
3. AlN: [Al]³⁺ [ :Ṇ: ]³⁻
4. MgS: [Mg]²⁺ [ :S̈: ]²⁻
5. FeCl₃: [Fe]³⁺ [ :Cl: ]⁻ [ :Cl: ]⁻ [ :Cl: ]⁻
6. CaF₂: [Ca]²⁺ [ :F: ]⁻ [ :F: ]⁻
7. Ag₃P: [Ag]⁺ [Ag]⁺ [Ag]⁺ [ :Ṗ: ]³⁻
8. Ba₃N₂: [Ba]²⁺ [Ba]²⁺ [Ba]²⁺ [ :Ṇ: ]³⁻ [ :Ṇ: ]³⁻
9. Al₂O₃: [Al]³⁺ [Al]³⁺ [ :Ö: ]²⁻ [ :Ö: ]²⁻ [ :Ö: ]²⁻
10. ZnI₂: [Zn]²⁺ [ :İ: ]⁻ [ :İ: ]⁻
11. Au₂S₃: [Au]³⁺ [Au]³⁺ [ :S̈: ]²⁻ [ :S̈: ]²⁻ [ :S̈: ]²⁻

Note: In all cases, the anions (negative ions) have 8 dots (4 pairs) representing their full valence shell after gaining electrons. Cations (positive ions) have no dots — they’ve lost their valence electrons. Charges are shown outside the brackets.