Protons, Neutrons, Electrons worksheet - Free Printable

Problem Analysis:

The task involves understanding the relationship between protons, neutrons, electrons, atomic numbers, and mass numbers for different elements. The first part focuses on Chlorine (Cl), and the second part requires filling out a table for various elements using the provided information.

#### Part 1: Chlorine (Cl)
We are given the symbol box for Chlorine:
- Atomic number: 17
- Mass number: 35

We need to determine:
1. Atomic number
2. Mass number
3. Number of electrons
4. Number of neutrons
5. Number of protons

#### Part 2: Filling the Table
We need to fill out the table for the following elements:
1. Element with mass number 24 and atomic number 11
2. Element with symbol "Y" and mass number 89, with 39 electrons
3. Element with atomic number 29 and 35 neutrons
4. Element with symbol "Tc" and 43 protons
5. Element with symbol "Pb" and mass number 207

Solution:

#### Part 1: Chlorine (Cl)

1. Atomic number: The atomic number is explicitly given as 17.
- Answer: 17

2. Mass number: The mass number is explicitly given as 35.
- Answer: 35

3. Number of electrons: The number of electrons in a neutral atom is equal to the atomic number.
- Atomic number = 17
- Answer: 17

4. Number of neutrons: The number of neutrons is calculated as:
\[
\text{Neutrons} = \text{Mass number} - \text{Atomic number}
\]
- Mass number = 35
- Atomic number = 17
- Neutrons = 35 - 17 = 18
- Answer: 18

5. Number of protons: The number of protons is equal to the atomic number.
- Atomic number = 17
- Answer: 17

#### Part 2: Filling the Table

We will use the relationships:
- Atomic number = Number of protons = Number of electrons (in a neutral atom)
- Mass number = Protons + Neutrons

##### Row 1: Element with mass number 24 and atomic number 11
- Atomic number = 11
- Mass number = 24
- Protons = Atomic number = 11
- Neutrons = Mass number - Protons = 24 - 11 = 13
- Electrons = Protons = 11
- Element symbol: Sodium (Na)

| Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons |
|----------------|-------------|---------------|---------|----------|-----------|
| Na | 24 | 11 | 11 | 13 | 11 |

##### Row 2: Element with symbol "Y" and mass number 89, with 39 electrons
- Electrons = 39
- Protons = Electrons = 39
- Atomic number = Protons = 39
- Neutrons = Mass number - Protons = 89 - 39 = 50
- Element symbol: Yttrium (Y)

| Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons |
|----------------|-------------|---------------|---------|----------|-----------|
| Y | 89 | 39 | 39 | 50 | 39 |

##### Row 3: Element with atomic number 29 and 35 neutrons
- Atomic number = 29
- Protons = Atomic number = 29
- Neutrons = 35
- Mass number = Protons + Neutrons = 29 + 35 = 64
- Electrons = Protons = 29
- Element symbol: Copper (Cu)

| Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons |
|----------------|-------------|---------------|---------|----------|-----------|
| Cu | 64 | 29 | 29 | 35 | 29 |

##### Row 4: Element with symbol "Tc" and 43 protons
- Protons = 43
- Atomic number = Protons = 43
- Mass number = 98 (given)
- Neutrons = Mass number - Protons = 98 - 43 = 55
- Electrons = Protons = 43
- Element symbol: Technetium (Tc)

| Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons |
|----------------|-------------|---------------|---------|----------|-----------|
| Tc | 98 | 43 | 43 | 55 | 43 |

##### Row 5: Element with symbol "Pb" and mass number 207
- Element symbol = Pb (Lead)
- Atomic number = 82 (from the periodic table or handout)
- Protons = Atomic number = 82
- Mass number = 207
- Neutrons = Mass number - Protons = 207 - 82 = 125
- Electrons = Protons = 82

| Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons |
|----------------|-------------|---------------|---------|----------|-----------|
| Pb | 207 | 82 | 82 | 125 | 82 |

Final Answer:

#### Part 1: Chlorine (Cl)
1. Atomic number: 17
2. Mass number: 35
3. Number of electrons: 17
4. Number of neutrons: 18
5. Number of protons: 17

#### Part 2: Filled Table
| Element Symbol | Mass Number | Atomic Number | Protons | Neutrons | Electrons |
|----------------|-------------|---------------|---------|----------|-----------|
| Na | 24 | 11 | 11 | 13 | 11 |
| Y | 89 | 39 | 39 | 50 | 39 |
| Cu | 64 | 29 | 29 | 35 | 29 |
| Tc | 98 | 43 | 43 | 55 | 43 |
| Pb | 207 | 82 | 82 | 125 | 82 |

Final Answer Box:
\boxed{
\begin{array}{|c|c|c|c|c|c|}
\hline
\text{Element Symbol} & \text{Mass Number} & \text{Atomic Number} & \text{Protons} & \text{Neutrons} & \text{Electrons} \\
\hline
\text{Na} & 24 & 11 & 11 & 13 & 11 \\
\hline
\text{Y} & 89 & 39 & 39 & 50 & 39 \\
\hline
\text{Cu} & 64 & 29 & 29 & 35 & 29 \\
\hline
\text{Tc} & 98 & 43 & 43 & 55 & 43 \\
\hline
\text{Pb} & 207 & 82 & 82 & 125 & 82 \\
\hline
\end{array}
}