Bohr Model Worksheet Form ≡ Fill Out Printable PDF Forms Online - Free Printable

Let's solve this Bohr Model Worksheet step by step. The goal is to draw the electron configuration for each element using the Bohr model, where:

- Inner electrons are drawn in blue
- Valence (outer) electrons are drawn in red
- Each circle represents an electron shell (energy level)
- Electrons are placed in shells according to the maximum capacity per shell:
- 1st shell: 2 electrons
- 2nd shell: 8 electrons
- 3rd shell: 8 electrons (for these elements, up to 8)
- 4th shell: starts filling after 3rd

We'll go through each element, determine its atomic number (number of electrons), then distribute electrons into shells, and finally identify which are inner (blue) and valence (red).

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🔹 Step-by-step Instructions:

1. Find the atomic number (number of protons/electrons).
2. Fill shells in order: 2 → 8 → 8 → ...
3. Inner electrons = all electrons except those in the outermost shell.
4. Valence electrons = electrons in the outermost shell.

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✔ Element-by-element Solution:

#### 1. Sodium (Na) – Atomic Number: 11
- Electrons: 11
- Shell distribution:
- 1st shell: 2 e⁻ (blue)
- 2nd shell: 8 e⁻ (blue)
- 3rd shell: 1 e⁻ (red)
- Answer:
- Blue: 2 + 8 = 10 inner electrons
- Red: 1 valence electron

✔ Draw:
- Inner (blue): 2 in first shell, 8 in second
- Outer (red): 1 in third shell

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#### 2. Aluminum (Al) – Atomic Number: 13
- Electrons: 13
- Distribution:
- 1st: 2 (blue)
- 2nd: 8 (blue)
- 3rd: 3 (red)
- Answer:
- Blue: 10 inner
- Red: 3 valence

✔ Draw:
- 2 blue in 1st, 8 blue in 2nd, 3 red in 3rd

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#### 3. Carbon (C) – Atomic Number: 6
- Electrons: 6
- Distribution:
- 1st: 2 (blue)
- 2nd: 4 (red)
- Answer:
- Blue: 2 inner
- Red: 4 valence

✔ Draw:
- 2 blue in 1st, 4 red in 2nd

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#### 4. Silicon (Si) – Atomic Number: 14
- Electrons: 14
- Distribution:
- 1st: 2 (blue)
- 2nd: 8 (blue)
- 3rd: 4 (red)
- Answer:
- Blue: 10 inner
- Red: 4 valence

✔ Draw:
- 2 blue in 1st, 8 blue in 2nd, 4 red in 3rd

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#### 5. Oxygen (O) – Atomic Number: 8
- Electrons: 8
- Distribution:
- 1st: 2 (blue)
- 2nd: 6 (red)
- Answer:
- Blue: 2 inner
- Red: 6 valence

✔ Draw:
- 2 blue in 1st, 6 red in 2nd

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#### 6. Chlorine (Cl) – Atomic Number: 17
- Electrons: 17
- Distribution:
- 1st: 2 (blue)
- 2nd: 8 (blue)
- 3rd: 7 (red)
- Answer:
- Blue: 10 inner
- Red: 7 valence

✔ Draw:
- 2 blue in 1st, 8 blue in 2nd, 7 red in 3rd

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#### 7. Fluorine (F) – Atomic Number: 9
- Electrons: 9
- Distribution:
- 1st: 2 (blue)
- 2nd: 7 (red)
- Answer:
- Blue: 2 inner
- Red: 7 valence

✔ Draw:
- 2 blue in 1st, 7 red in 2nd

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#### 8. Phosphorus (P) – Atomic Number: 15
- Electrons: 15
- Distribution:
- 1st: 2 (blue)
- 2nd: 8 (blue)
- 3rd: 5 (red)
- Answer:
- Blue: 10 inner
- Red: 5 valence

✔ Draw:
- 2 blue in 1st, 8 blue in 2nd, 5 red in 3rd

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#### 9. Lithium (Li) – Atomic Number: 3
- Electrons: 3
- Distribution:
- 1st: 2 (blue)
- 2nd: 1 (red)
- Answer:
- Blue: 2 inner
- Red: 1 valence

✔ Draw:
- 2 blue in 1st, 1 red in 2nd

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📝 Summary Table:

| Element | Atomic # | Electron Shells (Blue/Red) | Inner (Blue) | Valence (Red) |
|-------------|----------|-------------------------------------|--------------|----------------|
| Sodium (Na) | 11 | 2 (b), 8 (b), 1 (r) | 10 | 1 |
| Aluminum (Al)| 13 | 2 (b), 8 (b), 3 (r) | 10 | 3 |
| Carbon (C) | 6 | 2 (b), 4 (r) | 2 | 4 |
| Silicon (Si)| 14 | 2 (b), 8 (b), 4 (r) | 10 | 4 |
| Oxygen (O) | 8 | 2 (b), 6 (r) | 2 | 6 |
| Chlorine (Cl)| 17 | 2 (b), 8 (b), 7 (r) | 10 | 7 |
| Fluorine (F)| 9 | 2 (b), 7 (r) | 2 | 7 |
| Phosphorus (P)| 15 | 2 (b), 8 (b), 5 (r) | 10 | 5 |
| Lithium (Li)| 3 | 2 (b), 1 (r) | 2 | 1 |

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✔ How to Fill the Worksheet:

For each diagram:
- Draw dots (electrons) on each shell.
- Color inner electrons blue, valence electrons red.
- Use the correct number from the table above.

> 💡 Tip: The number of valence electrons can also be found from the group number (for main group elements):
> - Group 1: 1 valence e⁻
> - Group 2: 2
> - Group 13: 3
> - Group 14: 4
> - Group 15: 5
> - Group 16: 6
> - Group 17: 7
> - Group 18: 8 (except He)

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