Topic 4- Atomic Structure

Question 1

State 4 types of nuclear radiation

Answer 1

1. Alpha particles
2. Beta particles
3. Gamma rays
4. Neutrons

Question 2

What are the constituents of an alpha particle?

Answer 2

Two protons and two neutrons

The same as a helium nucleus

Question 3

What will stop beta radiation from passing through a point?

Answer 3

Thin sheet of aluminium

Several meters of air

Question 4

What will stop gamma radiation passing through a point?

Answer 4

Several cm of lead

A few cm of concrete

Question 5

Which type of radiation is most ionising?

Answer 5

Alpha

Question 6

Which type of radiation is least ionising?

Answer 6

Gamma

Question 7

What changes to mass and charge occur due to gamma ray emission?

Answer 7

Both stay the same

Question 8

What is the nature of radioactive decay?

Answer 8

Random- nuclei radiation is completely by chance

Impossible to predict

Question 9

Define the half life of a radioactive isotope

Answer 9

Time it takes for unstable nuclei in substance to halve

Question 10

What is radioactive contamination?

Answer 10

Presence of unwanted radioactive nuclei on other materials

Question 11

What is irradiation?

Answer 11

Process of exposing material to nuclear radiation

Material doesn’t become radioactive

Question 12

Which 2 ways can an atoms electron arrangement be changed?

Answer 12

1. Absorbing electromagnetic radiation

2. Emitting electromagnetic radiation

Question 13

How does an atoms electron arrangement change when it absorbs electromagnetic radiation?

Answer 13

Electrons move away from nucleus

Move to a higher energy level

Question 14

How does an atoms electron arrangement change when it emits electromagnetic radiation?

Answer 14

Electrons move close to nucleus

Move to lower energy level

Question 15

Give 4 sources of background radiation

Answer 15

1. Rocks
2. Cosmic rays from space
3. Nuclear weapon testing
4. Nuclear accidents

Question 16

What is the unit used to measure radiation dosage?

Answer 16

Sieverts

Question 17

Why might the radiation dosage different people experience differ?

Answer 17

Background radiation differs in different locations due to locality of nuclear power stations

Question 18

What factor determines how dangerous a particular radioactive isotope is?

Answer 18

The half- life of the isotope

Question 19

Why are isotopes with long half lives harmful?

Answer 19

• remain radioactive for long periods of time

- must be stored to prevent humans and the environment being exposed to radiation for too long

Question 20

State 2 uses of nuclear radiation in the field of medicine?

Answer 20

1. Examining internal organs

2. Controlling + destroying unwanted tissue

Question 21

How is radiation used in sterilisation?

Answer 21

Gamma emitters kill bacteria on equipment

Question 22

What is the process of radiotherapy?

Answer 22

1. Gamma emitters direct gamma rays at cancerous cells

2. Cancerous cells absorb radiation and are killed

Question 23

What is nuclear fission?

Answer 23

Splitting of large unstable nuclei from small stable nuclei

Question 24

What needs to happen to induce fission?

Answer 24

Unstable nuclei must absorb neutrons

Question 25

Alongside small nuclei, what else is emitted during fission?

Answer 25

Gamma rays
2/3 neutrons
Neutrons

Question 26

What form of energy do all fission products have?

Answer 26

Kinetic energy

Question 27

What takes place in a chain reaction?

Answer 27

• unstable nucleus absorbs neutron
• nucleus undergoes fission and emits 2/3 neutrons
• these induce more fission : chain reaction

Question 28

What is the consequence of an uncontrolled chain reaction?

Answer 28

Rate of events too high; too much energy production

Can lead to nuclear explosion