Determine the number of atomic number, mass number, proton ... - Free Printable

Let's solve the problem step by step using the information provided in the image and basic atomic structure principles.

We are given a table with elements: Lithium (Li), Beryllium (Be), Boron (B), and Nitrogen (N). We need to fill in missing values for:

- Atomic mass
- Number of electrons (e⁻)
- Number of protons (p⁺)
- Number of neutrons (n⁰)

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🔹 Key Concepts:

1. Atomic number (Z) = Number of protons (p⁺)
2. In neutral atoms, number of electrons (e⁻) = number of protons
3. Atomic mass (A) ≈ Mass number = protons + neutrons → so:
- Number of neutrons (n⁰) = Atomic mass − Atomic number
4. Atomic masses are usually given as average atomic masses (from periodic table).

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Now let’s complete the table row by row.

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1. Lithium (Li)

- Name: Lithium
- Atomic number: 3 → So, p⁺ = 3
- Electrons (e⁻): 3 (neutral atom)
- Atomic mass: From periodic table, 6.941 (rounded to 7 in some contexts, but we use 6.941)
- Neutrons (n⁰) = Atomic mass − Atomic number ≈ 6.941 − 3 ≈ 3.941 → But since neutrons must be whole numbers, we consider the most common isotope.

Actually, the most common isotope of lithium is Li-7, which has:
- 3 protons
- 4 neutrons
- So n⁰ = 4

But the atomic mass listed on the periodic table is 6.941, an average of isotopes (Li-6 and Li-7). For this exercise, since it says "atomic mass" and gives 6.941, we can use that.

So:
- Atomic mass: 6.941
- Number of e⁻: 3
- Number of p⁺: 3
- Number of n⁰: Since mass ≈ 7 (rounding), and protons = 3 → neutrons = 7 − 3 = 4

✔ So: n⁰ = 4

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2. Beryllium (Be)

- Name: Beryllium
- Atomic number: 4 → So, p⁺ = 4
- Electrons (e⁻): 4 (neutral atom)
- Atomic mass: From periodic table, 9.0122 → round to 9
- Neutrons (n⁰) = Atomic mass − Atomic number ≈ 9.0122 − 4 ≈ 5.0122 → So n⁰ = 5 (most stable isotope is Be-9)

Given in the table: n⁰ = 5 ✔

So:
- Atomic mass: 9.0122
- Number of e⁻: 4
- Number of p⁺: 4
- Number of n⁰: 5

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3. Boron (B)

- Name: Boron
- Atomic number: ? → Given Atomic mass = 11, and p⁺ = 5
- So Atomic number = 5 → because p⁺ = atomic number
- Electrons (e⁻) = 5 (neutral atom)
- Atomic mass: 11 (given)
- Neutrons (n⁰) = 11 − 5 = 6

So:
- Atomic number: 5
- Atomic mass: 11
- e⁻: 5
- p⁺: 5
- n⁰: 6

Note: Actual atomic mass of boron is 10.81, but here it's simplified to 11, probably referring to the isotope B-11.

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4. Nitrogen (N)

- Name: Nitrogen
- Atomic number: 7 → So p⁺ = 7
- Atomic mass: 14 (given)
- Electrons (e⁻) = 7 (neutral atom)
- Neutrons (n⁰) = 14 − 7 = 7

So:
- Atomic number: 7
- Atomic mass: 14
- e⁻: 7
- p⁺: 7
- n⁰: 7

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✔ Final Completed Table:

| Name of element | Atomic number | Atomic mass | Number of e⁻ | Number of p⁺ | Number of n⁰ |
|------------------|---------------|-------------|--------------|--------------|--------------|
| Lithium | 3 | 6.941 | 3 | 3 | 4 |
| Beryllium | 4 | 9.0122 | 4 | 4 | 5 |
| Boron | 5 | 11 | 5 | 5 | 6 |
| Nitrogen | 7 | 14 | 7 | 7 | 7 |

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🟩 Summary of Missing Values Filled In:

- Lithium: Atomic mass = 6.941, n⁰ = 4
- Beryllium: p⁺ = 4, atomic mass = 9.0122
- Boron: atomic number = 5, e⁻ = 5, n⁰ = 6
- Nitrogen: e⁻ = 7, p⁺ = 7, n⁰ = 7

This completes the table based on atomic structure rules and periodic table data.