Parts of an Atom interactive worksheet - Free Printable

Here's the complete solution to the worksheet, explained step-by-step.

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## PART 1: Parts of an Atom

Labeling the Diagram (a, b, c)

- a → Electron
*Explanation:* Electrons are negatively charged particles that orbit the nucleus in electron shells. In the diagram, “a” points to the small circles with minus signs (–) outside the central cluster — these are electrons.

- b → Proton
*Explanation:* Protons are positively charged particles located in the nucleus. In the diagram, “b” points to one of the small circles with plus signs (+) inside the central nucleus — these are protons.

- c → Neutron
*Explanation:* Neutrons are neutral (no charge) particles also found in the nucleus. In the diagram, “c” points to a circle without a charge symbol inside the nucleus — this is a neutron.

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Answering the Questions

1. Which subatomic particle has a negative charge?
→ Electron

2. Which subatomic particle has a positive charge?
→ Proton

3. Which subatomic particle has no charge?
→ Neutron

4. What determines an element’s identity?
→ Number of protons (also called the atomic number)
*Explanation:* Each element has a unique number of protons. For example, all atoms with 6 protons are carbon, regardless of how many neutrons or electrons they have.

5. How many protons does this atom have?
→ 8 protons
*Explanation:* Count the + symbols in the nucleus (labeled “b”). There are 8 protons.

6. How many neutrons does this atom have?
→ 8 neutrons
*Explanation:* Count the neutral particles in the nucleus (labeled “c”). There are 8 neutrons.

7. How many electrons does this atom have?
→ 8 electrons
*Explanation:* Count the – symbols orbiting the nucleus (labeled “a”). There are 8 electrons.
*Note:* In a neutral atom, the number of electrons equals the number of protons.

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## PART 2: Periodic Table & Chemical Symbols

You’re given the periodic table box for Oxygen (O):

```
8
O
Oxygen
15.999
```

Label the parts correctly:

- Top-left number (8) → Atomic number
*(This tells you the number of protons)*

- Letter in center (O) → Symbol

- Word below symbol (Oxygen) → Element name

- Bottom number (15.999) → Atomic mass
*(Average mass of all isotopes of the element)*

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Question: How many protons does this element have?

→ 8 protons
*Explanation:* The atomic number = number of protons. Since oxygen’s atomic number is 8, it has 8 protons.

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## ✔ Final Answers Summary:

Diagram Labels:

- a = Electron
- b = Proton
- c = Neutron

Short Answer Questions:

1. Electron
2. Proton
3. Neutron
4. Number of protons (atomic number)
5. 8
6. 8
7. 8

Periodic Table Labels:

- 8 → Atomic number
- O → Symbol
- Oxygen → Element name
- 15.999 → Atomic mass

Protons in Oxygen:

→ 8

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Let me know if you’d like a visual diagram labeled or further explanation!