Radioactivity — KCSE Chemistry

KCSE Chemistry · 52 practice questions · 4 syllabus objectives

10 easy25 medium17 hard

What You'll Learn

Key learning outcomes for this topic, aligned to the KNEC KCSE syllabus.

Define radioactivity and describe the properties of alpha (α), beta (β) and gamma (γ) radiation

Write nuclear equations for alpha and beta decay and explain what happens to atomic number and mass number

Define half-life and perform calculations involving radioactive decay and half-life

Radioactivity

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easySHORT ANSWER3 marks

List three properties of gamma (γ) radiation. (3 marks)

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Part (a) — 3 marks

Gamma radiation is electromagnetic radiation with no mass or charge (1 mk)

It has high penetrating power and can pass through most materials (1 mk)

Gamma rays are weakly ionising compared to alpha and beta radiation (1 mk)

easySHORT ANSWER3 marks

List three characteristics of alpha (α) radiation. (3 marks)

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Part (a) — 3 marks

Alpha particles consist of 2 protons and 2 neutrons (helium nucleus) (1 mk)

They have low penetrating power and can be stopped by paper or skin (1 mk)

Alpha radiation is highly ionising, causing significant damage to nearby tissues (1 mk)

easySHORT ANSWER4 marks

Identify the characteristics of gamma (γ) radiation and explain why it requires specific materials for effective shielding. (4 marks)

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Part (a) — 4 marks

Gamma rays are electromagnetic waves with no mass or charge (1 mk)

Gamma radiation has very high penetrating power, able to pass through most materials (1 mk)

Gamma rays have low ionising ability compared to alpha and beta radiation (1 mk)

Effective shielding requires dense materials like lead or thick concrete due to their high energy (1 mk)

Identify the main properties of beta (β) radiation and discuss how these properties affect its interactions with materials. (4 marks)