Topic 4-Atomic structure

Question 1

Where does radioactivity come from?

Answer 1

Given off by radioactive isotopes or unstable nuclei

Question 2

What is an alpha particle made up of?

Answer 2

2 protons and 2 neutrons (+2) (mass of 4)

It is the same as a helium nucleus

Question 3

What is a beta particle made up of?

Answer 3

1 high energy electron (-1)( mass of basically 0)

Question 4

What is a gamma particle made up?

Answer 4

It is a wave

No charge

No mass

Question 5

What are the characteristics of an alpha particle

Answer 5

• Highly ionising
• Weakly penetrating
• Can be stopped by a few cm of air, paper, skin

Question 6

What are the characteristics of a beta particle?

Answer 6

• Medium ionising
• Medium penetrating
• Can be stopped by few m of air or aluminium

Question 7

What does it mean if something is ionising?

Answer 7

It means it creates an ion

Question 8

What are some of the characteristics of a gamma particle?

Answer 8

• Low ionising

- Highly penetration

Question 9

What are some of the uses of alpha, beta and gamma particles?

Answer 9

Alpha- smoke detectors

Beta- Check thickness of paper

Gamma- Sterilisation or radiotherapy

Question 10

Why do unstable nuclei give out radiation?

Answer 10

• Unstable nuclei undergo decay to become more stable

- As they release radiation their stability increases

Question 11

What does ‘half-life’ mean?

Answer 11

It is the time taken for half the nuclei in a sample to decay

It cannot be predicted

Question 12

How can you protect yourself from radiation?

Answer 12

• Reduce time with radiation
• Stand far away
• Use gloves/screen

Question 13

What is the unit of radioactive activity?

Answer 13

Becquerel (Bq)

Question 14

Give an example of a detector that may be used to measure count-rate?

Answer 14

Geiger-Muller tube

Question 15

Describe the nature of radioactive decay

Answer 15

• Random
• Which nuclei decays and when is determined only chance
• It is impossible to predict which nuclei will decay and when

Question 16

What is irradiation?

Answer 16

• The process of exposing a material to nuclear radiation

- the material does not become radioactive

Question 17

Why is it important for the results of studies on the effects of radiation to be published and shared with other scientists?

Answer 17

• To allow the findings to be independently checked

- This is known as peer review

Question 18

How should background radiation be dealt with in calculations?

Answer 18

The background count should be subtracted from any readings before calculations are attmepted

Question 19

Why might the radiation dosage that different people experience differ?

Answer 19

• Some occupations involve working with radiation
• Background radiation differs with location due to things such as the locality of nuclear power stations or radiation related testing

Question 20

Explain why contamination of the inside of the human body by a radioactive material that emits alpha radiation is highly dangerous

Answer 20

Alpha particles are highly ionising. This can cause organ failure and radiation sickness until the radioactive material is removed