Atomic Number and Mass Worksheet for learning basic atomic structure.

It looks like you've uploaded a worksheet titled "Atomic Number and Mass Worksheet", which asks students to fill in missing information about various elements using the relationships:

- Atomic number = number of protons = number of electrons (in a neutral atom)
- Atomic mass ≈ protons + neutrons

Let’s go through each row and complete the missing values based on these rules.

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🔹 Step-by-step Solution

We’ll use the following formulas:
- Protons = Atomic Number
- Electrons = Protons (for neutral atoms)
- Neutrons = Atomic Mass – Protons

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#### 1. Boron
- Symbol: B
- Atomic Number: 5 → Protons = 5, Electrons = 5
- Atomic Mass: 11 → Neutrons = 11 - 5 = 6
✔ Completed:
Proton: 5
Neutron: 6
Electron: 5

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#### 2. Phosphorus
- Symbol: P
- Atomic Number: 15 → Protons = 15, Electrons = 15
- Atomic Mass: 31 → Neutrons = 31 - 15 = 16
✔ Completed:
Proton: 15
Neutron: 16
Electron: 15

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#### 3. Calcium
- Symbol: Ca
- Atomic Number: 20 → Protons = 20, Electrons = 20
- Atomic Mass: 40 → Neutrons = 40 - 20 = 20
✔ Completed:
Proton: 20
Neutron: 20
Electron: 20

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#### 4. Argon
- Symbol: Ar
- Atomic Number: 18 → Protons = 18, Electrons = 18
- Atomic Mass: 40 → Neutrons = 40 - 18 = 22
✔ Completed:
Proton: 18
Neutron: 22
Electron: 18

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#### 5. Carbon
- Symbol: C
- Atomic Number: 6 → Protons = 6, Electrons = 6
- Atomic Mass: 12 → Neutrons = 12 - 6 = 6
✔ Completed:
Proton: 6
Neutron: 6
Electron: 6

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#### 6. Beryllium
- Symbol: Be
- Atomic Number: 4 → Protons = 4, Electrons = 4
- Atomic Mass: 9 → Neutrons = 9 - 4 = 5
✔ Completed:
Proton: 4
Neutron: 5
Electron: 4

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#### 7. Lithium
- Symbol: Li
- Atomic Number: 3 → Protons = 3, Electrons = 3
- Atomic Mass: 7 → Neutrons = 7 - 3 = 4
✔ Completed:
Proton: 3
Neutron: 4
Electron: 3

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#### 8. Chlorine
- Symbol: Cl
- Atomic Number: 17 → Protons = 17, Electrons = 17
- Atomic Mass: 35 → Neutrons = 35 - 17 = 18
✔ Completed:
Proton: 17
Neutron: 18
Electron: 17

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#### 9. Aluminum
- Symbol: Al
- Atomic Number: 13 → Protons = 13, Electrons = 13
- Atomic Mass: 27 → Neutrons = 27 - 13 = 14
✔ Completed:
Proton: 13
Neutron: 14
Electron: 13

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#### 10. Potassium
- Symbol: K
- Atomic Number: 19 → Protons = 19, Electrons = 19
- Atomic Mass: 39 → Neutrons = 39 - 19 = 20
✔ Completed:
Proton: 19
Neutron: 20
Electron: 19

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#### 11. Fluorine
- Symbol: F
- Atomic Number: 9 → Protons = 9, Electrons = 9
- Atomic Mass: 19 → Neutrons = 19 - 9 = 10
✔ Completed:
Proton: 9
Neutron: 10
Electron: 9

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✔ Final Answer Table (Completed)

| Element | Symbol | Atomic Number | Atomic Mass | Proton | Neutron | Electron |
|-------------|--------|---------------|-------------|--------|---------|----------|
| Boron | B | 5 | 11 | 5 | 6 | 5 |
| Phosphorus | P | 15 | 31 | 15 | 16 | 15 |
| Calcium | Ca | 20 | 40 | 20 | 20 | 20 |
| Argon | Ar | 18 | 40 | 18 | 22 | 18 |
| Carbon | C | 6 | 12 | 6 | 6 | 6 |
| Beryllium | Be | 4 | 9 | 4 | 5 | 4 |
| Lithium | Li | 3 | 7 | 3 | 4 | 3 |
| Chlorine | Cl | 17 | 35 | 17 | 18 | 17 |
| Aluminum | Al | 13 | 27 | 13 | 14 | 13 |
| Potassium | K | 19 | 39 | 19 | 20 | 19 |
| Fluorine | F | 9 | 19 | 9 | 10 | 9 |

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📌 Summary of Key Concepts:

- The atomic number tells you how many protons are in the nucleus.
- In a neutral atom, the number of electrons equals the number of protons.
- The atomic mass is approximately the sum of protons and neutrons.
- So, neutrons = atomic mass – atomic number.

This worksheet helps reinforce understanding of atomic structure and how to interpret periodic table data.

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