Bohr model practice - Chemistry periodic table - Name: Date ... - Free Printable

The image you've uploaded is a Bohr Model Practice worksheet where students are asked to:

1. Write the total number of electrons for each element.
2. Draw or color in the correct number of electrons in each electron shell (orbit), following the rule that:
- Electrons fill the innermost shells first.
- Each shell has a maximum capacity:
- 1st shell (closest to nucleus): 2 electrons
- 2nd shell: 8 electrons
- 3rd shell: 8 electrons (for these elements)
- 4th shell: 8 electrons (for these elements)

Let’s go through each element and verify the correct number of electrons, and then check if the Bohr diagrams are correctly drawn.

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✔ Step-by-step Analysis:

#### 1. Sodium (Na)
- Atomic number = 11 → So, it has 11 electrons
- Electron configuration:
- 1st shell: 2 electrons
- 2nd shell: 8 electrons
- 3rd shell: 1 electron
- The diagram shows 2 + 8 + 1 = 11 electrons → ✔ Correct

#### 2. Potassium (K)
- Atomic number = 19 → So, it has 19 electrons
- Electron configuration:
- 1st shell: 2
- 2nd shell: 8
- 3rd shell: 8
- 4th shell: 1
- Total: 2+8+8+1 = 19 electrons → ✔ Correct

#### 3. Hydrogen (H)
- Atomic number = 1 → So, it has 1 electron
- Only one electron in the 1st shell → ✔ Correct

#### 4. Carbon (C)
- Atomic number = 6 → So, it has 6 electrons
- Configuration:
- 1st shell: 2
- 2nd shell: 4
- Total: 2+4 = 6 electrons → ✔ Correct

#### 5. Silicon (Si)
- Atomic number = 14 → So, it has 14 electrons
- Configuration:
- 1st shell: 2
- 2nd shell: 8
- 3rd shell: 4
- Total: 2+8+4 = 14 electrons → ✔ Correct

#### 6. Oxygen (O)
- Atomic number = 8 → So, it has 8 electrons
- Configuration:
- 1st shell: 2
- 2nd shell: 6
- Total: 2+6 = 8 electrons → ✔ Correct

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🔍 Summary of Answers (as written on the worksheet):

| Element | Number of Electrons |
|--------|---------------------|
| Sodium (Na) | 11 ✔ |
| Potassium (K) | 19 ✔ |
| Hydrogen (H) | 1 ✔ |
| Carbon (C) | 6 ✔ |
| Silicon (Si) | 14 ✔ |
| Oxygen (O) | 8 ✔ |

✔ All numbers are correct.

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🧠 Explanation of How to Fill Electron Shells (Bohr Model Rules):

1. Electron Capacity per Shell:
- 1st shell (n=1): max 2 electrons
- 2nd shell (n=2): max 8 electrons
- 3rd shell (n=3): max 8 electrons (for atoms up to ~20)
- 4th shell (n=4): max 8 electrons (in this context)

2. Fill from inside out: Always fill the innermost shell completely before moving outward.

3. Use the Periodic Table: The atomic number tells you how many electrons a neutral atom has.

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✔ Final Answer:

All answers on the worksheet are correct:
- Sodium: 11
- Potassium: 19
- Hydrogen: 1
- Carbon: 6
- Silicon: 14
- Oxygen: 8

And the Bohr diagrams appear to be filled correctly according to the rules.

> 💡 Tip: When drawing Bohr models, remember that electrons are placed as dots around the circles (shells), and they should be evenly spaced, but not paired unless necessary. For example, in oxygen (8 electrons), the second shell has 6 electrons — which can be shown as three pairs or six single dots.

If you're coloring them, just ensure no shell exceeds its limit and all electrons are accounted for.

✔ This worksheet is completed correctly!