Atomic structure worksheet | PDF - Free Printable

Problem Description:

The task involves filling in the blanks for the elements in the provided chart. The chart includes the following columns:
1. Element: The name of the element.
2. Number of Protons: The number of protons in the nucleus of the atom.
3. Number of Neutrons: The number of neutrons in the nucleus of the atom.
4. Number of Electrons: The number of electrons in the neutral atom.
5. Atomic Mass: The approximate mass of the atom (sum of protons and neutrons).
6. Atomic Number: The number of protons in the nucleus, which uniquely identifies the element.

The solution key is partially filled, and we need to complete it based on the rules of atomic structure.

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Solution Explanation:

#### Key Concepts:
1. Atomic Number: The atomic number is equal to the number of protons in the nucleus. It also equals the number of electrons in a neutral atom.
2. Atomic Mass: The atomic mass is approximately equal to the sum of the number of protons and neutrons in the nucleus.
3. Neutral Atom: In a neutral atom, the number of electrons equals the number of protons.

#### Step-by-Step Analysis:

1. Lithium (Li):
- Atomic Number = 3 (given).
- Number of Protons = Atomic Number = 3.
- Number of Electrons = Number of Protons = 3.
- Atomic Mass = 7 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 7 - 3 = 4.

2. Carbon (C):
- Atomic Number = 6 (given).
- Number of Protons = Atomic Number = 6.
- Number of Electrons = Number of Protons = 6.
- Atomic Mass = 12 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 12 - 6 = 6.

3. Chlorine (Cl):
- Atomic Number = 17 (given).
- Number of Protons = Atomic Number = 17.
- Number of Electrons = Number of Protons = 17.
- Atomic Mass = 35 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 35 - 17 = 18.

4. Silver (Ag):
- Atomic Number = 47 (given).
- Number of Protons = Atomic Number = 47.
- Number of Electrons = Number of Protons = 47.
- Atomic Mass = 108 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 108 - 47 = 61.

5. Lead (Pb):
- Atomic Number = 82 (given).
- Number of Protons = Atomic Number = 82.
- Number of Electrons = Number of Protons = 82.
- Atomic Mass = 207 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 207 - 82 = 125.

6. Calcium (Ca):
- Atomic Number = 20 (given).
- Number of Protons = Atomic Number = 20.
- Number of Electrons = Number of Protons = 20.
- Atomic Mass = 40 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 40 - 20 = 20.

7. Tantalum (Ta):
- Atomic Number = 73 (given).
- Number of Protons = Atomic Number = 73.
- Number of Electrons = Number of Protons = 73.
- Atomic Mass = 181 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 181 - 73 = 108.

8. Radium (Ra):
- Atomic Number = 88 (given).
- Number of Protons = Atomic Number = 88.
- Number of Electrons = Number of Protons = 88.
- Atomic Mass = 226 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 226 - 88 = 138.

9. Samarium (Sm):
- Atomic Number = 62 (given).
- Number of Protons = Atomic Number = 62.
- Number of Electrons = Number of Protons = 62.
- Atomic Mass = 150 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 150 - 62 = 88.

10. Uranium (U):
- Atomic Number = 92 (given).
- Number of Protons = Atomic Number = 92.
- Number of Electrons = Number of Protons = 92.
- Atomic Mass = 238 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 238 - 92 = 146.

11. Americium (Am):
- Atomic Number = 95 (given).
- Number of Protons = Atomic Number = 95.
- Number of Electrons = Number of Protons = 95.
- Atomic Mass = 243 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 243 - 95 = 148.

12. Lawrencium (Lr):
- Atomic Number = 103 (given).
- Number of Protons = Atomic Number = 103.
- Number of Electrons = Number of Protons = 103.
- Atomic Mass = 262 (given).
- Number of Neutrons = Atomic Mass - Number of Protons = 262 - 103 = 159.

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Final Answer:

The completed chart is as follows:

| Element | Number of Protons | Number of Neutrons | Number of Electrons | Atomic Mass | Atomic Number |
|---------------|-------------------|--------------------|---------------------|-------------|---------------|
| Lithium | 3 | 4 | 3 | 7 | 3 |
| Carbon | 6 | 6 | 6 | 12 | 6 |
| Chlorine | 17 | 18 | 17 | 35 | 17 |
| Silver | 47 | 61 | 47 | 108 | 47 |
| Lead | 82 | 125 | 82 | 207 | 82 |
| Calcium | 20 | 20 | 20 | 40 | 20 |
| Tantalum | 73 | 108 | 73 | 181 | 73 |
| Radium | 88 | 138 | 88 | 226 | 88 |
| Samarium | 62 | 88 | 62 | 150 | 62 |
| Uranium | 92 | 146 | 92 | 238 | 92 |
| Americium | 95 | 148 | 95 | 243 | 95 |
| Lawrencium | 103 | 159 | 103 | 262 | 103 |

$$
\boxed{
\begin{array}{|c|c|c|c|c|c|}
\hline
\text{Element} & \text{Number of Protons} & \text{Number of Neutrons} & \text{Number of Electrons} & \text{Atomic Mass} & \text{Atomic Number} \\
\hline
\text{Lithium} & 3 & 4 & 3 & 7 & 3 \\
\text{Carbon} & 6 & 6 & 6 & 12 & 6 \\
\text{Chlorine} & 17 & 18 & 17 & 35 & 17 \\
\text{Silver} & 47 & 61 & 47 & 108 & 47 \\
\text{Lead} & 82 & 125 & 82 & 207 & 82 \\
\text{Calcium} & 20 & 20 & 20 & 40 & 20 \\
\text{Tantalum} & 73 & 108 & 73 & 181 & 73 \\
\text{Radium} & 88 & 138 & 88 & 226 & 88 \\
\text{Samarium} & 62 & 88 & 62 & 150 & 62 \\
\text{Uranium} & 92 & 146 & 92 & 238 & 92 \\
\text{Americium} & 95 & 148 & 95 & 243 & 95 \\
\text{Lawrencium} & 103 & 159 & 103 & 262 & 103 \\
\hline
\end{array}
}
$$