III. Nuclear Chemistry

What is alpha radiation?

A type of radiation made of 2 protons and 2 neutrons (like a helium nucleus), with a +2 charge.
📌 Weakest penetration—stopped by paper or skin.

What is beta radiation?

Radiation made of a fast-moving electron with a –1 charge.
📌 Medium strength – stopped by aluminum or plastic.

What is gamma radiation?

Pure energy (no mass, no charge).
📌 Most dangerous – needs lead or thick concrete for shielding.

What does the term "half-life" mean?

The time it takes for half of a radioactive substance to decay.
📌 Used to measure how long a substance stays active.

How much of a substance is left after 3 half-lives?

A: 12.5% (because:

• After 1 half-life → 50%

• After 2 → 25%

• After 3 → 12.5%)

What kind of material blocks alpha particles?

Paper, skin, or even clothes.

What material blocks beta particles?

Plastic, glass, or aluminum.

What material blocks gamma rays?

Lead or thick concrete.

What kind of radiation is used in cancer treatment to destroy tumors?

Gamma radiation is very powerful and can penetrate deep into tissues.