Protons, Neutrons, and Electrons Practice Worksheet For 8th Grade ... - Free Printable

The image you've uploaded is a "Protons, Neutrons, and Electrons Practice Worksheet" that helps students calculate the number of protons, neutrons, and electrons in various atoms using the periodic table.

Let me walk through how to solve this worksheet step by step and verify the answers provided (some are already filled in). The key formulas used are:

- # Protons = Atomic Number
- # Electrons = # Protons (in neutral atoms)
- # Neutrons = Mass Number – Atomic Number

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🔍 Step-by-Step Explanation

For each element, we use the following information from the periodic table:
- Atomic Number: Number of protons.
- Mass Number: Approximate mass of the atom (usually rounded to nearest whole number).
- Electrons: Equal to protons in a neutral atom.
- Neutrons: Mass Number − Atomic Number.

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✔ Let's Verify Each Row:

| Element | Symbol | Mass # | Atomic # | Protons | Neutrons | Electrons |
|--------|--------|--------|----------|---------|----------|-----------|
| Boron | B | 11 | 5 | 5 | 6 | 5 |
| Sodium | Na | 24 | 11 | 11 | 13 | 11 |
| Yttrium| Y | 89 | 39 | 39 | 50 | 39 |
| Copper | Cu | 64 | 29 | 29 | 35 | 29 |
| Technetium | Tc | 98 | 43 | 43 | 55 | 43 |
| Lead | Pb | 207 | 82 | 82 | 125 | 82 |
| Thallium | Tl | 204 | 81 | 81 | 123 | 81 |
| Hydrogen | H | 1 | 1 | 1 | 0 | 1 |
| Carbon | C | 12 | 6 | 6 | 6 | 6 |
| Nitrogen | N | 14 | 7 | 7 | 7 | 7 |
| Barium | Ba | 137 | 56 | 56 | 81 | 56 |
| Calcium| Ca | 40 | 20 | 20 | 20 | 20 |
| Silicon| Si | 28 | 14 | 14 | 14 | 14 |
| Argon | Ar | 40 | 18 | 18 | 32 | 18 |
| Magnesium | Mg | 24 | 12 | 12 | 12 | 12 |

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🔎 Verification of Calculations:

1. Boron (B)
- Atomic #: 5 → Protons = 5
- Mass #: 11 → Neutrons = 11 – 5 = 6
- Electrons = 5 ✔

2. Sodium (Na)
- Atomic #: 11 → Protons = 11
- Mass #: 24 → Neutrons = 24 – 11 = 13
- Electrons = 11 ✔

3. Yttrium (Y)
- Atomic #: 39 → Protons = 39
- Mass #: 89 → Neutrons = 89 – 39 = 50 ✔

4. Copper (Cu)
- Atomic #: 29 → Protons = 29
- Mass #: 64 → Neutrons = 64 – 29 = 35 ✔

5. Technetium (Tc)
- Atomic #: 43 → Protons = 43
- Mass #: 98 → Neutrons = 98 – 43 = 55 ✔

6. Lead (Pb)
- Atomic #: 82 → Protons = 82
- Mass #: 207 → Neutrons = 207 – 82 = 125 ✔

7. Thallium (Tl)
- Atomic #: 81 → Protons = 81
- Mass #: 204 → Neutrons = 204 – 81 = 123 ✔

8. Hydrogen (H)
- Atomic #: 1 → Protons = 1
- Mass #: 1 → Neutrons = 1 – 1 = 0 (most common isotope: protium) ✔
- Electrons = 1 ✔

9. Carbon (C)
- Atomic #: 6 → Protons = 6
- Mass #: 12 → Neutrons = 12 – 6 = 6 ✔

10. Nitrogen (N)
- Atomic #: 7 → Protons = 7
- Mass #: 14 → Neutrons = 14 – 7 = 7 ✔

11. Barium (Ba)
- Atomic #: 56 → Protons = 56
- Mass #: 137 → Neutrons = 137 – 56 = 81 ✔

12. Calcium (Ca)
- Atomic #: 20 → Protons = 20
- Mass #: 40 → Neutrons = 40 – 20 = 20 ✔

13. Silicon (Si)
- Atomic #: 14 → Protons = 14
- Mass #: 28 → Neutrons = 28 – 14 = 14 ✔

14. Argon (Ar)
- Atomic #: 18 → Protons = 18
- Mass #: 40 → Neutrons = 40 – 18 = 32 ✔

15. Magnesium (Mg)
- Atomic #: 12 → Protons = 12
- Mass #: 24 → Neutrons = 24 – 12 = 12 ✔

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✔ Final Answer Summary:

All values in the completed table are correct, assuming:
- The mass numbers given are for the most common isotopes.
- All atoms are neutral (no ions), so electrons = protons.

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📌 Key Takeaways:

- Use the atomic number for protons and electrons.
- Use mass number – atomic number for neutrons.
- Always check if the atom is neutral (which it is here).

If you have any specific questions about one of the elements or need help finding values on the periodic table, let me know!