Topic 3 - Radioactivity and Ionising Radiation

Question 1

What is the relative mass of a neutron

Answer 1

1

Question 2

What is the relative mass of an electron

Answer 2

1/2000

Question 3

What is the relative charge of a proton

Answer 3

+1

Question 4

What is the relative charge of a neutron

Answer 4

0

Question 5

What is the relative charge of a electron

Answer 5

-1

Question 6

What are the three types of radiation

Answer 6

Alpha

Beta

Gamma

Question 7

What are the properties of alpha radiation?

Answer 7

Helium nucleus

Slow and heavy

Strongly ionising

Stopped by paper skin etc

Question 8

What are the properties of beta radiation

Answer 8

An electron

Light and fast

Moderately ionising

Stopped by thin metal

Question 9

What are the properties of gamma radiation?

Answer 9

Electronic radiation

No mass very fast

Weakly ionising

Stopped by thick lead or very thick concrete

Question 10

What is a positron

Answer 10

A positron is the antiparticle of the electron. Same properties as electron except relative charge is +1.

Question 11

What is annihilation?

Answer 11

When a positron and electron collide they are obliterated

Question 12

What are the properties of neutron radiation?

Answer 12

Neutrons

More penetrating than alpha or beta and sometimes even more penetrating than gamma.

Not directly ionising but can be absorbed by the nuclei of atoms.

Emit ionising radiation - indirectly ionising

Absorbed by light nuclei

Absorption often makes nuclei emit gamma radiation

Question 13

What makes a nucleus unstable

Answer 13

Too many/few neutrons

Too many protons and neutrons (too heavy)

Too much energy

Question 14

What is the relative mass of a proton

Answer 14

1

Question 15

what is an NZ graph

Answer 15

a graph that compares the number of protons and neutrons in an element.

Question 16

What happens to elements above the curve of stability

Answer 16

too many neutrons B- decay

Question 17

What happens to elements below the curve of stability

Answer 17

too few neutrons B+ decay

Question 18

When does b- decay happen

Answer 18

when there are too many neutrons. It emits an electron from the nucleus and a neutron is changed into a proton.

Question 19

What happens in b- decay

Answer 19

emission of electron from the nucleus. Neutron changes to proton the atomic number increases by one the mass number stays the same

Question 20

when does b+ decay happen

Answer 20

when there are too few neutrons. Emits positron from the nucleus and proton gets changed to neutron.

Question 21

what happens in b+ decay

Answer 21

emission of positron from nucleus

proton changes to neutron

atomic number decreases by one

mass stays the same

Question 22

when does alpha decay happen

Answer 22

happens in heavy nuclei (more than 82 protons)

Question 23

what happens in alpha decay

Answer 23

proton number increases by two nucleon number decreases by four

Question 24

when does gamma radiation happen

Answer 24

happens when nuclei has too much energy often happens after b or a decay

Question 25

what happens in gamma radiation

Answer 25

nuclei loses energy no change to atomic or mass number never just gamma emitted

Question 26

What are quarks

Answer 26

smaller particles that make up protons and neutrons

Question 27

What is the relative mass and charge of an up quark

Answer 27

mass: 1/3 charge: 2/3

Question 28

What is the relative mass and charge of a down quark

Answer 28

mass: 1/3 charge: -1/3

Question 29

What quarks make up a proton

Answer 29

up up down

Question 30

what quarks make up a neutron

Answer 30

down down up

Question 31

What happens in b- decay in terms of quarks

Answer 31

a down quark changes to an up quark

Question 32

what happens in b+ decay in terms of quarks

Answer 32

an up quark changes to a down quark

Question 33

what must be equal before and after radioactive decay

Answer 33

the charge