P7 - Radioactivity

Question 1

What is nuclear radiation?

Answer 1

When the nucleus of an atom emits radiation because it is unstable

Question 2

Why would a nucleus be unstable and emit radiation?

Answer 2

The nucleus has too many protons
The nucleus has too many neutrons
The nucleus is too large

Question 3

What are the four types of nuclear radiation we need to know for gcse?

Answer 3

Alpha particles
Beta particles
Gamma rays
Neutrons

Question 4

How did Ernest Rutherford decide to test JJ Thompsons plum pudding model?

Answer 4

He aimed alpha particles at thin gold foil to detect the alpha particles path

Question 6

After Rutherford alpha particle experiment, what did he deduce?

Answer 6

The nucleus is where most of the mass is located
The nucleus is postively charged because it repels the alpha particle
The nucleus is much smaller than the atom because alpha particles pass through without deflection

Question 7

What is the atomic structure of an alpha particle?

Answer 7

Made of 2 protons and 2 neutrons

Question 8

What is the charge and mass of an alpha particle?

Answer 8

Charge of 2+
Mass of 4

Question 9

How many protons + neutrons are lost when an atom emits alpha decay?

Answer 9

2 protons + 2 neutrons

Question 10

How are Beta particles formed?

Answer 10

One of an atoms neutrons decay into an proton an an electron.
The proton stays in the nucleus and the electron is emitted out st high speed
We call this electron a Beta Particle

Question 11

What is the charge and mass of a beta particle?

Answer 11

Charge of -1
Mass of 0

Question 12

What is Gamma Radiation emitted by?

Answer 12

Unstable nuclei

Question 13

Why cant alpha particles penetrate very far into other materials?

Answer 13

Because they are relatively large, they are easily stopped by collisions with other molecules

Question 14

How far can alpha particles travel?

Answer 14

A few cm in air and can be absorbed by a single sheet of paper

Question 15

Because Alpha particles are relatively large, they are strongly ionising. What does this mean?

Answer 15

They can easily knock electrons off any atoms that they collide with

Question 16

Why can Beta particles penetrate moderately far into other materials?

Answer 16

Because they are tiny and are emitted at high speeds

Question 17

How far can beta particles travel?

Answer 17

Several meters of air and are absorbed by 5mm of aluminium

Question 18

Why are gamma rays not classified as particles?

Answer 18

They are waves of electromagnetic radiation

Question 20

What is the charge and mass of gamma rays?

Answer 20

No charge and no mass

Question 21

Why do gamma rays pass through materials easily?

Answer 21

They don’t have any mass or charge that can collide with any atoms

Question 22

Are gamma rays weakly ionising?

Answer 22

Yes 👍

Question 23

How far can gamma particles penetrate?

Answer 23

Long distances through air and is absorbed by thick sheets of lead

Question 24

When does the emission of a neutron occur

Answer 24

If a nucleus is unstable because there is too many neutrons, they can just throw unneeded ones out

Question 25

What is the frequency of the decay process?

Answer 25

It is completely random

Question 26

What does the activity of a sample mean?

Answer 26

The overall rate of decay of all the isotopes in our sample

Question 27

What is activity measured in?

Answer 27

Becquerels Where 1Bq = 1 decay per second

Question 28

What are the two definitions of half life?

Answer 28

The time taken for the number of radioactive nuclei in a sample to halve The time taken for the number of decays or activity to halve

Question 30

What is irradiation?

Answer 30

The process by which objects are exposed to radiation

Question 31

What is contamination?

Answer 31

When radioactive particles get onto other objects

Question 32

What determines how harmful radiation can be to humans?

Answer 32

The type of radiation Where your exposed to it The amount of radiation recieved

Question 33

What type of radiation is most dangerous?

Answer 33

The ionising ones

Question 34

Why are the ionising radiations dangerous to humans?

Answer 34

They enter into living cells and ionise our DNA This leads to cells mutating uncontrollably which leads to cancer

Question 35

What are two uses of radiation in medicine?

Answer 35

Radiotherapy Medical tracers

Question 36

What is radiotherapy?

Answer 36

Using radiation to destroy particular cells in our body like cancer cells

Question 37

What are the two ways of delivering radiotherapy to cancer patients?

Answer 37

Externally and internally

Question 38

How does the external treatment using radiotherapy work?

Answer 38

Emitting gamma rays at the cancer site from all angles

Question 39

How does the internal treatment using radiotherapy work?

Answer 39

Placing beta particles inside the cancer

Question 40

Why would professionals place beta particles inside the body instead of gamma rays?

Answer 40

Even though beta particles are more damaging, they cant penetrate far through the body

Question 41

What are the side effects of radiotherapy in cancer patients?

Answer 41

It also kills healthy cells

Question 42

What are medical tracers?

Answer 42

Tracing the movement of radioactive isotopes that are injected into people go check if organs are working properly

Question 43

What is nuclear fission

Answer 43

The splitting up of large and unstable nuclei into smaller nuclei

Question 44

What are the two ways that stimulate nuclear fission to take place?

Answer 44

Spontaneously or when Absorbing a neutron

Question 45

Explain the process of nuclear fission.

Answer 45

A slow neutron is fired at a large, unstable nuclei The additional neutron makes the nuclei even more unstable snd cause it to split apart into two daughter nuclei. This process releases 2-3 neutrons and lots of energy. The neutrons released repeat this process

Question 46

How do nuclear reactors control the rate of nuclear fission?

Answer 46

Control rods in the reactor to absorb neutrons

Question 47

What are the pros of nuclear energy?

Answer 47

Fuel is cheap Doesn't produce greenhouse gases

Question 48

What are the cons of nuclear energy?

Answer 48

Power plants are very expensive to build Nuclear waste is also hard and expensive to get rid of Still a risk of disaster although its small

Question 49

What is nuclear fusion?

Answer 49

When two light nuclei join or fuse to form a single large nuclei

Question 50

During nuclear fusion, what is released?

Answer 50

A lot of energy

Question 51

Why is nuclear fusion a fundamental in life?

Answer 51

Its how all elements heavier than hydrogen were made

Question 52

Why does nuclear fusion release so much energy?

Answer 52

Some of the mass of the original nuclei is converted to energy rather than transferred to the new nucleus

Question 53

What is the pros about nuclear fusion?

Answer 53

It doesn't produce any radioactive waste

Question 54

What is a con about nuclear fusion for humans?

Answer 54

It only occurs at extremely high temperatures and pressures (10 000 000°C) so it can not be done on earth

Question 55

What are the differences between nuclear fusion and nuclear fission

Answer 55

Fusion is the fusing of light nuclei to make heavier nuclei | fission is where large, unstable nuclei are split into two smaller nuclei Fusion only happens in stars | fission can happen anywhere with right conditions Fusion produces tons of energy | fission produces lots as well but nowhere as much as fusion

Question 56

Name the element that changes into radon when it decays

Answer 56

Radium (Ra)