Free Printable Protons Neutrons and Electrons Practice Worksheets - Free Printable

To solve this worksheet, we need to determine the number of protons, neutrons, and electrons for each element listed. Here's how we do it:

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🔍 Key Concepts:

1. Number of Protons = Atomic Number (found on the periodic table).
2. Number of Electrons = Number of Protons (in a neutral atom).
3. Number of Neutrons = Mass Number – Atomic Number
- The mass number is typically the most common isotope’s mass (often rounded to nearest whole number).
- For simplicity, we use the most abundant stable isotope unless otherwise specified.

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Let’s fill in the table using standard atomic data:

| Element | Number of Protons | Number of Neutrons | Number of Electrons |
|--------------|-------------------|--------------------|---------------------|
| Hydrogen | 1 | 0 | 1 |
| Oxygen | 8 | 8 | 8 |
| Gold | 79 | 118 | 79 |
| Carbon | 6 | 6 | 6 |
| Nitrogen | 7 | 7 | 7 |
| Helium | 2 | 2 | 2 |
| Iron | 26 | 30 | 26 |
| Silicon | 14 | 14 | 14 |
| Chlorine | 17 | 18 | 17 |
| Sodium | 11 | 12 | 11 |
| Fluorine | 9 | 10 | 9 |
| Aluminum | 13 | 14 | 13 |
| Phosphorus | 15 | 16 | 15 |
| Magnesium | 12 | 12 | 12 |
| Radium | 88 | 138 | 88 |
| Uranium | 92 | 146 | 92 |
| Plutonium | 94 | 144 | 94 |

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✔ Explanation of Each Entry:

#### 1. Hydrogen
- Atomic number: 1 → 1 proton
- Most common isotope: H-1 → 0 neutrons
- Electrons = protons = 1

#### 2. Oxygen
- Atomic number: 8 → 8 protons
- Most common isotope: O-16 → 16 – 8 = 8 neutrons
- Electrons = 8

#### 3. Gold (Au)
- Atomic number: 79 → 79 protons
- Most common isotope: Au-197 → 197 – 79 = 118 neutrons
- Electrons = 79

#### 4. Carbon
- Atomic number: 6 → 6 protons
- Most common isotope: C-12 → 12 – 6 = 6 neutrons
- Electrons = 6

#### 5. Nitrogen
- Atomic number: 7 → 7 protons
- Most common isotope: N-14 → 14 – 7 = 7 neutrons
- Electrons = 7

#### 6. Helium
- Atomic number: 2 → 2 protons
- Isotope: He-4 → 4 – 2 = 2 neutrons
- Electrons = 2

#### 7. Iron (Fe)
- Atomic number: 26 → 26 protons
- Most common isotope: Fe-56 → 56 – 26 = 30 neutrons
- Electrons = 26

#### 8. Silicon (Si)
- Atomic number: 14 → 14 protons
- Most common isotope: Si-28 → 28 – 14 = 14 neutrons
- Electrons = 14

#### 9. Chlorine (Cl)
- Atomic number: 17 → 17 protons
- Most common isotope: Cl-35 → 35 – 17 = 18 neutrons
- Electrons = 17

#### 10. Sodium (Na)
- Atomic number: 11 → 11 protons
- Most common isotope: Na-23 → 23 – 11 = 12 neutrons
- Electrons = 11

#### 11. Fluorine (F)
- Atomic number: 9 → 9 protons
- Most common isotope: F-19 → 19 – 9 = 10 neutrons
- Electrons = 9

#### 12. Aluminum (Al)
- Atomic number: 13 → 13 protons
- Most common isotope: Al-27 → 27 – 13 = 14 neutrons
- Electrons = 13

#### 13. Phosphorus (P)
- Atomic number: 15 → 15 protons
- Most common isotope: P-31 → 31 – 15 = 16 neutrons
- Electrons = 15

#### 14. Magnesium (Mg)
- Atomic number: 12 → 12 protons
- Most common isotope: Mg-24 → 24 – 12 = 12 neutrons
- Electrons = 12

#### 15. Radium (Ra)
- Atomic number: 88 → 88 protons
- Most common isotope: Ra-226 → 226 – 88 = 138 neutrons
- Electrons = 88

#### 16. Uranium (U)
- Atomic number: 92 → 92 protons
- Most common isotope: U-238 → 238 – 92 = 146 neutrons
- Electrons = 92

#### 17. Plutonium (Pu)
- Atomic number: 94 → 94 protons
- Most common isotope: Pu-239 → 239 – 94 = 145 neutrons
*(Note: Some sources say Pu-244; but Pu-239 is more commonly referenced in practice)*
However, the most stable isotope is Pu-244 → 244 – 94 = 150 neutrons.
But Pu-239 is the most common in nuclear applications.

For consistency with typical classroom data, we'll use Pu-239 → 145 neutrons.

But wait — let’s double-check:
Actually, Pu-244 has a longer half-life (more stable), so some textbooks use that.
But since the question doesn’t specify, we’ll go with the most common isotope used in practice: Pu-239.

So:
- Protons: 94
- Neutrons: 239 – 94 = 145
- Electrons: 94

> ⚠️ Note: In real-world contexts, isotopes vary. This worksheet likely expects standard values.

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✔ Final Answer Table:

| Element | Number of Protons | Number of Neutrons | Number of Electrons |
|--------------|-------------------|--------------------|---------------------|
| Hydrogen | 1 | 0 | 1 |
| Oxygen | 8 | 8 | 8 |
| Gold | 79 | 118 | 79 |
| Carbon | 6 | 6 | 6 |
| Nitrogen | 7 | 7 | 7 |
| Helium | 2 | 2 | 2 |
| Iron | 26 | 30 | 26 |
| Silicon | 14 | 14 | 14 |
| Chlorine | 17 | 18 | 17 |
| Sodium | 11 | 12 | 11 |
| Fluorine | 9 | 10 | 9 |
| Aluminum | 13 | 14 | 13 |
| Phosphorus | 15 | 16 | 15 |
| Magnesium | 12 | 12 | 12 |
| Radium | 88 | 138 | 88 |
| Uranium | 92 | 146 | 92 |
| Plutonium | 94 | 145 | 94 |

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📌 Notes:

- All values assume neutral atoms.
- Neutron numbers are based on most abundant or common isotopes.
- For radioactive elements like Uranium and Plutonium, these are the most stable/common isotopes.

✔ This completes the worksheet! Let me know if you'd like a printable version or explanation for any specific element.