2.7 - Types of radiation

Question 1

What do all forms of the same element have in common?

Answer 1

The number of protons

Question 2

What is the name given to the number of protons in an atom?

Answer 2

Atomic number

Proton number

Question 3

What is an atom’s mass number (Nucleon number)?

Answer 3

The total number of protons and neutrons in the atom

Question 4

What is an isotope of an atom?

Answer 4

An atom of the same element that has a different number of neutrons (so a different mass number), but the same number of protons

Question 5

What are the properties of the following 3 sub-atomic particles with respect to relative mass and relative charge:
Proton
Neutron
Electron

Answer 5

Proton:
Mass: 1
Charge: +1

Neutron:
Mass: 1
Charge: 0

Electron:
Mass: almost 0
Charge: -1

Question 6

The number of electrons in an atom is always the same as the number of _____, so atoms are electrically neutral overall. Atoms can lose or gain _____. When they do, they form charged particles called ions:

Answer 6

protons

electrons

Question 7

Why are atoms radioactive?

Answer 7

There is an imbalance between the numbers of protos and neutrons which makes it unstable

Question 8

Why do unstable nuclei give out radiation?

Answer 8

Unstable nuclei undergo decay to become more stable.

As they release radiation their stability increases

Question 9

What is the name of the process in which an unstable nucleus gives out radiation to become stable?

Answer 9

Radioactive decay

Question 10

State the 3 main types of ionising radiation emitted from the unstable nuclei of radioactive atoms?

Answer 10

Alpha, beta and gamma radiation.

Question 11

What does an alpha particle consists of?

Answer 11

Two protons and two neutrons

It is the same as a helium nucleus

Question 12

What will stop alpha radiation from passing through a point?

Answer 12

A few cm of air, skin or a thin sheet of paper

Question 13

What is the ionising power of an alpha particle?

Answer 13

Very high - most damaging inside the body

Question 14

What does an beta particle consist of?

Answer 14

High-energy electrons emitted from the nucleus.

Question 15

What will stop beta radiation from passing through a point?

Answer 15

A thin sheet of aluminium

Several metres of air

Question 16

What is a gamma ray?

Answer 16

High energy electromagnetic wave

Question 17

What will stop gamma radiation from passing through a point?

Answer 17

Several cm’s of lead

A few metres of concreate

Question 18

Which type of radiation is most ionising?

Answer 18

Alpha radiation

Question 19

Which type of radiation is least ionising?

Answer 19

Gamma radiation

Question 20

Which type of radiation is least penetrating?

Answer 20

Alpha radiation

Question 21

Which type of radiation is most penetrating?

Answer 21

Gamma radiation

Question 22

State any changes to mass or charge that occur due to the emission of a gamma ray.

Answer 22

Both mass and charge remain uncharged

Question 23

State any changes to mass or charge that occur due to the emission of a beta particle.

Answer 23

Mass remains unchanged, charge increases by 1

Question 24

State any changes to mass or charge that occur due to the emission of an alpha particle.

Answer 24

Mass decreases by 4 and charge decreases by 2

Question 25

Describe the nature of radioactive decay.

Answer 25

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

Question 26

State two techniques that can be used when carrying out experimental work, to combat the random nature of decay

Answer 26

1. Take repeat-readings

2. Carry the experiment out over a long period of time

Question 27

Why is radioactive waste such a problem?

Answer 27

It remains radioactive for thousands of years

It can cause harm to living cells so must be stored appropriately

Question 28

How is nuclear waste disposed of?

Answer 28

1) cooled in large water tanks
2) Then turned into a type of glass so it can’t flow
3) Then placed inside a steel drum and sealed in concreate
4) Then buried deep underground

Question 29

Most background radiation coms from natural sources. Give some examples.

Answer 29

1. Radon
2. Cosmic rays from space
3. Rocks
4. Food and buildings

Question 30

Some background radiation comes from artificial sources. Give some examples.

Answer 30

1. Nuclear industry (nuclear weapon testing, nuclear accidents)
2. Medical industry (X-rays)

Question 31

What is half life?

Answer 31

The time taken for the number of nuclei of the isotope in a sample to halve

Question 32

Alpha decay:

Two protons and two neutrons are lost from a nucleus when it emits an alpha particle. This means that:

the atomic mass number decreases by _
the atomic number decreases by _

A new element is formed that is two places to the left in the periodic table than the original element.

Answer 32

4

2

Question 33

In beta decay, a neutron changes into a ____ plus an _____. The proton stays in the nucleus. The electron leaves the atom with high energy as a beta particle.

The nucleus has one more proton and one less neutron when it emits a beta particle. This means that:

the atomic mass number stays the same
the atomic number increases by 1

Answer 33

proton

electron