Completed Radioactivity Worksheet with answers filled in by hand.

The image you've uploaded is a Radioactivity Worksheet with answers already filled in. Below, I will solve and explain each part of the worksheet to ensure clarity and understanding.

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1. State the number of neutrons and protons in each nucleus

To find:
- Protons = Atomic number (Z)
- Neutrons = Mass number (A) – Atomic number (Z)

#### a. \( ^2_1H \)
- Protons = 1
- Neutrons = 2 – 1 = 1
✔ Correct

#### b. \( ^{12}_6C \)
- Protons = 6
- Neutrons = 12 – 6 = 6
✔ Correct

#### c. \( ^{56}_{26}Fe \)
- Protons = 26
- Neutrons = 56 – 26 = 30
✔ Correct

#### d. \( ^{197}_{79}Au \)
- Protons = 79
- Neutrons = 197 – 79 = 118
✔ Correct

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2. Complete the table for radioactive emissions

| Type | Charge | Atomic Symbol | Can Be Stopped By |
|----------|--------|----------------|--------------------|
| Alpha | +2 | \( ^4_2He \) | Paper |
| Beta | -1 | \( ^0_{-1}e \) | Aluminum |
| Gamma | 0 | \( ^0_0\gamma \)| Lead |

✔ All entries are correct.

#### Explanation:
- Alpha (α): Helium nucleus (2 protons + 2 neutrons), charge +2, stopped by paper.
- Beta (β): High-speed electron, charge -1, stops in aluminum.
- Gamma (γ): High-energy photon, no mass or charge, requires lead to stop.

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3. Match statements to radiation types

a) These emissions are charged.
→ α, β
✔ Alpha (+2), Beta (-1) are charged; Gamma is neutral.

b) This emission is the most massive (heaviest).
→ α
✔ Alpha particles are helium nuclei — heavier than electrons (beta) or photons (gamma).

c) This emission is the most charged.
→ α
✔ Alpha has +2 charge; beta has -1; gamma has 0.

d) This emission is most dangerous outside of the body.
→ γ
✔ Gamma rays penetrate deeply, so they’re more dangerous externally. Alpha is blocked easily but dangerous if ingested.

e) This emission is stopped by thin paper or a few cm of air.
→ α
✔ Alpha particles are stopped by paper or skin.

f) This emission can travel through paper, but is stopped by aluminum.
→ β
✔ Beta penetrates paper but blocked by metal like aluminum.

g) This emission can travel through fairly thick lead.
→ γ
✔ Gamma rays require thick lead or concrete to stop.

✔ All answers are correct.

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4. Which type of radiation...

#### a) Results in the greatest change in atomic number? Why?

> Answer: Alpha – changes by 2
✔ Correct
When an atom emits an alpha particle (\( ^4_2He \)), it loses 2 protons, so the atomic number decreases by 2. This is the largest change among the three.

#### b) Results in the least change in atomic number? Why?

> Answer: Gamma – no change in atomic number
✔ Correct
Gamma emission is just energy release (photon), no particles emitted, so atomic number remains unchanged.

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✔ Summary: The worksheet is fully completed correctly!

All answers provided in the image are accurate and well-reasoned.

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