Educational worksheet on atoms, ions, and isotopes with a table for students to fill in missing information.

Let's solve this step by step. We need to fill in the missing information for each substance using the relationships between atomic number, mass number, protons, neutrons, and electrons.

Key Concepts:

- Atomic Number (Z) = Number of protons
- Mass Number (A) = Protons + Neutrons
- Number of Electrons:
- In a neutral atom: Electrons = Protons
- In a positive ion: Electrons < Protons
- In a negative ion: Electrons > Protons
- Isotope: Same element (same atomic number), different mass number (due to different neutrons)
- Ion: Charged particle due to gain/loss of electrons

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We'll go row by row:

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1. Aluminum
- Symbol: Al
- Mass Number: 27
- Protons: 13 → Atomic Number = 13
- Electrons: 13 → same as protons → Neutral Atom
- Neutrons = Mass – Protons = 27 – 13 = 14

✔ Answer:
- Atomic Number: 13
- Neutrons: 14
- Type: Neutral Atom

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2. Bromine
- Atomic Number: 35 → Protons = 35
- Mass Number: 80
- Neutrons: 45 (given)
- Electrons: 36
- Since electrons (36) > protons (35), it's a Negative Ion (charge = -1)

✔ Answer:
- Symbol: Br
- Protons: 35
- Neutrons: 45
- Electrons: 36
- Type: Negative Ion

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3. Uranium
- Symbol: U
- Atomic Number: 92 → Protons = 92
- Neutrons: 146
- Electrons: 92 → same as protons → Neutral Atom
- Mass Number = Protons + Neutrons = 92 + 146 = 238

✔ Answer:
- Mass Number: 238
- Type: Neutral Atom

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4. Helium
- Symbol: He
- Atomic Number: 2 → Protons = 2
- Mass Number: 4
- Neutrons = 4 – 2 = 2
- Electrons = 2 → neutral → Neutral Atom

✔ Answer:
- Neutrons: 2
- Electrons: 2
- Type: Neutral Atom

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5. Helium (again)
- Symbol: He
- Atomic Number: 2 → Protons = 2
- Mass Number: 5
- Neutrons = 5 – 2 = 3
- Electrons: 2 → same as protons → Neutral Atom

✔ Answer:
- Neutrons: 3
- Type: Neutral Atom

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6. Lithium
- Atomic Number: 3 → Protons = 3
- Mass Number: 7
- Neutrons = 7 – 3 = 4
- Electrons: 2 → less than protons → Positive Ion (charge = +1)

✔ Answer:
- Neutrons: 4
- Type: Positive Ion

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7. Tungsten
- Symbol: W
- Mass Number: 184
- Neutrons: 110
- Electrons: 74
- Protons = Mass – Neutrons = 184 – 110 = 74
- So Atomic Number = 74 → matches Tungsten
- Electrons = 74 → equal to protons → Neutral Atom

✔ Answer:
- Atomic Number: 74
- Protons: 74
- Type: Neutral Atom

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8. Xenon
- Given: Neutrons = 79, Electrons = 54, Type = Neutral Atom
- Since neutral: Electrons = Protons → Protons = 54 → Atomic Number = 54
- Symbol: Xe
- Mass Number = Protons + Neutrons = 54 + 79 = 133

✔ Answer:
- Symbol: Xe
- Atomic Number: 54
- Mass Number: 133
- Protons: 54
- Type: Neutral Atom

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9. Magnesium
- Symbol: Mg
- Mass Number: 24
- Protons: 12 → Atomic Number = 12
- Type: Positive 2 ion → lost 2 electrons → Electrons = 12 – 2 = 10
- Neutrons = 24 – 12 = 12

✔ Answer:
- Atomic Number: 12
- Neutrons: 12
- Electrons: 10
- Type: Positive 2 ion

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10. Carbon
- Atomic Number: 6 → Protons = 6
- Neutrons: 6
- Type: Neutral Atom → Electrons = 6
- Mass Number = 6 + 6 = 12

✔ Answer:
- Mass Number: 12
- Symbol: C
- Electrons: 6
- Type: Neutral Atom

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11. Carbon
- Symbol: C
- Mass Number: 14
- Protons: 6 → Atomic Number = 6
- Neutrons: 8 (given)
- Electrons: ?
- Since no charge mentioned, but different from previous carbon (mass 12), it's an isotope.
- But is it neutral? Let's assume neutral unless stated otherwise.
- So electrons = 6 → Neutral Atom

✔ Answer:
- Atomic Number: 6
- Electrons: 6
- Type: Isotope (same element, different mass)

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12. Nitrogen
- Atomic Number: 7 → Protons = 7
- Mass Number: 14
- Neutrons = 14 – 7 = 7
- Electrons: ?
- Not specified, but if not charged, then electrons = 7 → Neutral Atom
- But we need to check if it’s an ion or isotope.
- Common nitrogen has mass 14, so this is likely neutral and common isotope.

✔ Answer:
- Protons: 7
- Neutrons: 7
- Electrons: 7
- Type: Neutral Atom

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Now let's compile all answers into the table:

| Substance | Symbol | Atomic Number | Mass Number | Protons | Neutrons | Electrons | Type |
|---------------|--------|----------------|-------------|---------|----------|-----------|-----------------------|
| Aluminum | Al | 13 | 27 | 13 | 14 | 13 | Neutral Atom |
| Bromine | Br | 35 | 80 | 35 | 45 | 36 | Negative Ion |
| Uranium | U | 92 | 238 | 92 | 146 | 92 | Neutral Atom |
| Helium | He | 2 | 4 | 2 | 2 | 2 | Neutral Atom |
| Helium | He | 2 | 5 | 2 | 3 | 2 | Neutral Atom |
| Lithium | Li | 3 | 7 | 3 | 4 | 2 | Positive Ion |
| Tungsten | W | 74 | 184 | 74 | 110 | 74 | Neutral Atom |
| Xenon | Xe | 54 | 133 | 54 | 79 | 54 | Neutral Atom |
| Magnesium | Mg | 12 | 24 | 12 | 12 | 10 | Positive 2 ion |
| Carbon | C | 6 | 12 | 6 | 6 | 6 | Neutral Atom |
| Carbon | C | 6 | 14 | 6 | 8 | 6 | Isotope |
| Nitrogen | N | 7 | 14 | 7 | 7 | 7 | Neutral Atom |

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Final Notes:

- Isotopes are atoms of the same element (same atomic number) with different mass numbers (different neutrons). The second Carbon (C-14) is an isotope of Carbon-12.
- Ions have unequal protons and electrons.
- Neutral atoms have equal protons and electrons.

✔ All blanks filled correctly!