Atomic Structure Worksheet for learning about atomic composition and periodic table elements.

Let's go through the Atomic Structure Worksheet step by step and solve each part.

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1. Using the periodic table, write the name of the element next to each atom.

We are given three atomic diagrams. Let’s analyze each one based on the number of protons (nucleus) and electrons (orbitals).

#### Atom 1:
- Nucleus has 3 black dots → 3 protons
- Electrons: 2 in first shell, 1 in second shell → total 3 electrons
- Atomic number = 3 → Element is Lithium (Li)

✔ Answer: Lithium

#### Atom 2:
- Nucleus has 8 black dots → 8 protons
- Electrons: 2 in first shell, 6 in second shell → total 8 electrons
- Atomic number = 8 → Element is Oxygen (O)

✔ Answer: Oxygen

#### Atom 3:
- Nucleus has 5 black dots → 5 protons
- Electrons: 2 in first shell, 3 in second shell → total 5 electrons
- Atomic number = 5 → Element is Boron (B)

✔ Answer: Boron

> Final Answers for #1:
> - First atom: Lithium
> - Second atom: Oxygen
> - Third atom: Boron

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2. Draw the following atoms.

We need to draw Bohr models (electron shells) for:

#### Hydrogen (H):
- Atomic number = 1 → 1 proton, 1 electron
- Electron configuration: 1 electron in the first shell

```
•
/
O
```

Or simply:
- A nucleus with one dot inside
- One electron in the first energy level (circle around nucleus)

#### Boron (B):
- Atomic number = 5 → 5 protons, 5 electrons
- Electron configuration: 2 in first shell, 3 in second shell

```
• •
/ \
O •
/ \
• •
```

(First circle: 2 electrons; second circle: 3 electrons)

#### Helium (He):
- Atomic number = 2 → 2 protons, 2 electrons
- Electron configuration: 2 electrons in the first shell (full)

```
• •
/
O
```

(Both electrons in the first shell)

> ✔ You can sketch these using circles for shells and dots for electrons.

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3. Fill in the blanks.

Given the oxygen box:

```
8
O
Oxygen
15.999
```

Label what each part means:

- 8 → Atomic Number
- O → Chemical Symbol
- Oxygen → Element Name
- 15.999 → Atomic Mass

So fill in:

- 8 → Atomic Number
- O → Chemical Symbol
- Oxygen → Element Name
- 15.999 → Atomic Mass

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#### What parts of an atom does the atomic number represent?

The atomic number represents:
- Number of protons and
- Number of electrons (in a neutral atom)

✔ Answer: protons and electrons

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#### How do you figure the number of neutrons?

Use the formula:

> Neutrons = Atomic mass (rounded) – Atomic number

For example:
- Oxygen: 16 (rounded) – 8 = 8 neutrons

✔ Answer: Subtract the atomic number from the atomic mass (rounded to nearest whole number).

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Now calculate for Carbon and Potassium

#### Carbon (C):
- Atomic number = 6 → protons = 6
- Neutral atom → electrons = 6
- Atomic mass ≈ 12.003 → rounded to 12
- Neutrons = 12 – 6 = 6

✔ So:
- # of protons: 6
- # of electrons: 6
- # of neutrons: 6

#### Potassium (K):
- Atomic number = 19 → protons = 19
- Electrons = 19 (neutral)
- Atomic mass ≈ 39.098 → rounded to 39
- Neutrons = 39 – 19 = 20

✔ So:
- # of protons: 19
- # of electrons: 19
- # of neutrons: 20

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✔ Final Answers Summary:

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#### 1. Element Names:
- First atom: Lithium
- Second atom: Oxygen
- Third atom: Boron

#### 2. Draw Atoms:
- Hydrogen: 1 proton, 1 electron in first shell
- Boron: 5 protons, 2 electrons in first shell, 3 in second
- Helium: 2 protons, 2 electrons in first shell

#### 3. Fill in the blanks:
- 8 → Atomic Number
- O → Chemical Symbol
- Oxygen → Element Name
- 15.999 → Atomic Mass

- Atomic number represents: protons and electrons

- How to find neutrons: Atomic mass (rounded) – Atomic number

#### Carbon (C):
- Protons: 6
- Electrons: 6
- Neutrons: 6

#### Potassium (K):
- Protons: 19
- Electrons: 19
- Neutrons: 20

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Let me know if you'd like a visual version of the drawings or a printable PDF-style answer!