Worksheet on parts of an atom and periodic table elements.

Here's the complete solution and explanation for the worksheet:

---

PART 1: Parts of an Atom

#### Labeling the Diagram:
- a → Electron (the small circles with “–” signs orbiting the nucleus)
- b → Proton (the particles with “+” signs inside the nucleus)
- c → Neutron (the neutral particles inside the nucleus — no charge symbol)

> *Note: In the diagram, the nucleus contains 4 protons (+) and 4 neutrons (no symbol). The electrons (–) are in orbits around the nucleus. There are 4 electrons shown.*

---

#### Answer 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)

5. How many protons does this atom have?
→ 4 (count the “+” symbols in the nucleus)

6. How many neutrons does this atom have?
→ 4 (count the neutral particles in the nucleus — there are 4 white circles without charge symbols)

7. How many electrons does this atom have?
→ 4 (count the “–” symbols orbiting the nucleus)

> *This atom is Beryllium (Be), since it has 4 protons. In a neutral atom, number of electrons = number of protons.*

---

PART 2: Periodic Table & Chemical Symbols

You are given the element box for Oxygen (O):

```
8
O
Oxygen
15.999
```

You need to label each part with:
→ atomic mass, element name, symbol, atomic number

#### Correct Labels:

- 8 → Atomic number (number of protons)
- O → Symbol
- Oxygen → Element name
- 15.999 → Atomic mass (average mass of atoms of that element)

#### Question: How many protons does this element have?
→ 8 (because atomic number = number of protons)

---

✔ Final Answers Summary:

#### Diagram Labels:
- a = Electron
- b = Proton
- c = Neutron

#### Questions:
1. Electron
2. Proton
3. Neutron
4. Number of protons (or atomic number)
5. 4
6. 4
7. 4

#### Periodic Table Box:
- 8 → Atomic number
- O → Symbol
- Oxygen → Element name
- 15.999 → Atomic mass
- Protons in Oxygen = 8

---

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