Protons, Neutrons, Electrons worksheet - Free Printable

Let me work through this step by step.

Part 1: Chlorine (Cl) symbol box questions

The symbol box shows:
- Atomic number: 17 (top number)
- Symbol: Cl
- Name: Chlorine
- Mass number: 35 (bottom number)

Key relationships:
- Atomic number = number of protons
- In a neutral atom, electrons = protons
- Neutrons = Mass number - Atomic number

So for Chlorine:
- Atomic number = 17
- Mass number = 35
- Electrons = 17 (same as protons in neutral atom)
- Neutrons = 35 - 17 = 18
- Protons = 17

Part 2: Table

Row 1: Mass Number = 24, Atomic Number = 11
- Element with atomic number 11 = Sodium (Na)
- Protons = 11
- Electrons = 11
- Neutrons = 24 - 11 = 13

Row 2: Y, Mass Number = 89, Electrons = 39
- Y is Yttrium
- Atomic number = 39 (since electrons = protons in neutral atom)
- Protons = 39
- Neutrons = 89 - 39 = 50

Row 3: Atomic Number = 29, Neutrons = 35
- Element with atomic number 29 = Copper (Cu)
- Protons = 29
- Electrons = 29
- Mass Number = 29 + 35 = 64

Row 4: Tc, Mass Number = 98, Protons = 43
- Tc is Technetium
- Atomic number = 43
- Electrons = 43
- Neutrons = 98 - 43 = 55

Row 5: Pb, Mass Number = 207
- Pb is Lead
- Atomic number of Lead = 82
- Protons = 82
- Electrons = 82
- Neutrons = 207 - 82 = 125

Let me verify all calculations:
- Row 1: Na, 24, 11, 11, 13, 11 ✓
- Row 2: Y, 89, 39, 39, 50, 39 ✓
- Row 3: Cu, 64, 29, 29, 35, 29 ✓
- Row 4: Tc, 98, 43, 43, 55, 43 ✓
- Row 5: Pb, 207, 82, 82, 125, 82 ✓

All checks out!

Final Answer:

Chlorine Symbol Box:
- Atomic number: 17
- Mass number: 35
- Electrons: 17
- Neutrons: 18
- Protons: 17

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 |