Isotopes and Nuclear Radiation

Question 1

Give the definition of the term ‘isotopes’.

Answer 1

Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons

Question 2

What is ionising radiation?

Answer 2

Any radiation that can knock electrons from atoms

Question 3

What is the process of radioactive decay?

Answer 3

This is when unstable isotopes decay into other elements, giving out radiation as they try to become more stable

Question 4

Some nuclear radiation is ionising.

State three types of ionising radiation emitted by radioactive decay.

Answer 4

• Alpha
• Beta
• Gamma

Question 5

What are the properties of alpha?

Answer 5

• Alpha radiation is when an alpha particle is emitted from the nucleus
• An alpha particle is two neutrons and two protons (the equivalent to a helium nucleus)
• Doesn’t penetrate very far into materials / stopped quickly
• Can travel a few cm in air / absorbed by thin paper
• Strongly ionising because of their size

Question 6

What are the properties of beta?

Answer 6

• A beta-minus particle is a fast-moving electron released by nucleus
• A beta-plus particle is a fast-moving positron (antiparticle of electron)
• Both are moderately ionising
• Beta-minus particles have range in air of a few metres / are absorbed by sheet of aluminium (around 5mm thick)
• Positrons have a smaller range

Question 7

What are the properties of gamma?

Answer 7

• Gamma rays are waves of electromagnetic radiation released by nucleus to carry away excess energy
• Penetrate far into materials / will travel long distance through air
• Weakly ionising
• Can be absorbed by thick sheets of lead / metres of concrete

Question 8

After a nucleus has decayed, it often undergoes nuclear rearrangement.

Describe what is meant by this.

Answer 8

This is when the nucleus releases some energy in the form of gamma rays

Question 9

(Exam-style question)

Answer 9