Electron arrangement worksheet with Bohr models for various elements.

Let's solve this step by step. The task is to complete the Bohr model for each element by:

1. Drawing electrons in the correct energy levels (shells) based on the electron configuration.
2. Filling in the number of protons, neutrons, electrons, atomic number, and atomic mass.

We’ll go through each element one at a time using information from the periodic table.

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🔬 Key Concepts:

- Atomic Number = number of protons = number of electrons (in neutral atom)
- Atomic Mass ≈ protons + neutrons (rounded to nearest whole number)
- Neutrons = Atomic Mass – Atomic Number
- Electron shells fill in order: 2 in first shell, 8 in second, 8 in third, etc.

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## ✔ Step-by-Step Solutions

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1. Hydrogen (H)

- Atomic Number: 1 → Protons = 1, Electrons = 1
- Atomic Mass: ~1.008 → Rounded to 1
- Neutrons: 1 - 1 = 0
- Electron Arrangement: 1 electron in the first shell

Bohr Model:
Draw 1 dot in the innermost circle (first shell).

| Protons | 1 |
|--------|---|
| Neutrons | 0 |
| Electrons | 1 |
| Atomic Number | 1 |
| Atomic Mass | 1 |

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2. Carbon (C)

- Atomic Number: 6 → Protons = 6, Electrons = 6
- Atomic Mass: ~12.01 → Rounded to 12
- Neutrons: 12 - 6 = 6
- Electron Configuration: 2 in first shell, 4 in second shell

Bohr Model:
- First shell: 2 dots
- Second shell: 4 dots

| Protons | 6 |
|--------|---|
| Neutrons | 6 |
| Electrons | 6 |
| Atomic Number | 6 |
| Atomic Mass | 12 |

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3. Oxygen (O)

- Atomic Number: 8 → Protons = 8, Electrons = 8
- Atomic Mass: ~16.00 → 16
- Neutrons: 16 - 8 = 8
- Electron Configuration: 2 in first shell, 6 in second shell

Bohr Model:
- First shell: 2 dots
- Second shell: 6 dots

| Protons | 8 |
|--------|---|
| Neutrons | 8 |
| Electrons | 8 |
| Atomic Number | 8 |
| Atomic Mass | 16 |

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4. Sulfur (S)

- Atomic Number: 16 → Protons = 16, Electrons = 16
- Atomic Mass: ~32.07 → 32
- Neutrons: 32 - 16 = 16
- Electron Configuration: 2, 8, 6 → 2 in first, 8 in second, 6 in third

Bohr Model:
- Shell 1: 2 dots
- Shell 2: 8 dots
- Shell 3: 6 dots

| Protons | 16 |
|--------|----|
| Neutrons | 16 |
| Electrons | 16 |
| Atomic Number | 16 |
| Atomic Mass | 32 |

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5. Nitrogen (N)

- Atomic Number: 7 → Protons = 7, Electrons = 7
- Atomic Mass: ~14.01 → 14
- Neutrons: 14 - 7 = 7
- Electron Configuration: 2, 5 → 2 in first, 5 in second

Bohr Model:
- Shell 1: 2 dots
- Shell 2: 5 dots

| Protons | 7 |
|--------|---|
| Neutrons | 7 |
| Electrons | 7 |
| Atomic Number | 7 |
| Atomic Mass | 14 |

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6. Boron (B)

- Atomic Number: 5 → Protons = 5, Electrons = 5
- Atomic Mass: ~10.81 → 11
- Neutrons: 11 - 5 = 6
- Electron Configuration: 2, 3 → 2 in first, 3 in second

Bohr Model:
- Shell 1: 2 dots
- Shell 2: 3 dots

| Protons | 5 |
|--------|---|
| Neutrons | 6 |
| Electrons | 5 |
| Atomic Number | 5 |
| Atomic Mass | 11 |

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7. Helium (He)

- Atomic Number: 2 → Protons = 2, Electrons = 2
- Atomic Mass: ~4.00 → 4
- Neutrons: 4 - 2 = 2
- Electron Configuration: 2 in first shell (full)

Bohr Model:
- Only one shell, with 2 dots

| Protons | 2 |
|--------|---|
| Neutrons | 2 |
| Electrons | 2 |
| Atomic Number | 2 |
| Atomic Mass | 4 |

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## ✔ Final Answer Summary Table

| Element | Protons | Neutrons | Electrons | Atomic Number | Atomic Mass |
|------------|---------|----------|-----------|----------------|-------------|
| Hydrogen | 1 | 0 | 1 | 1 | 1 |
| Carbon | 6 | 6 | 6 | 6 | 12 |
| Oxygen | 8 | 8 | 8 | 8 | 16 |
| Sulfur | 16 | 16 | 16 | 16 | 32 |
| Nitrogen | 7 | 7 | 7 | 7 | 14 |
| Boron | 5 | 6 | 5 | 5 | 11 |
| Helium | 2 | 2 | 2 | 2 | 4 |

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## 🎯 How to Draw the Bohr Models

For each element:
- Start with the nucleus (blue dot).
- Draw concentric circles (shells).
- Place electrons as small dots around the nucleus, following the 2, 8, 8... rule.

Example: Oxygen

- 1st shell: 2 electrons (dots)
- 2nd shell: 6 electrons (dots)
- Total: 8 electrons

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✔ You can now fill in the worksheet with these values and draw the electrons accordingly!

Let me know if you'd like a visual sketch or printable version!