P6.1 - Radioactive Emissions

Question 1

What is the mass of a proton?

Answer 1

1

Question 2

What is the mass of an electron?

Answer 2

1/2000

Question 3

what is the mass of a neutron?

Answer 3

1

Question 4

what is the relative charge of a neutron?

Answer 4

0

Question 5

what is the relative charge of an electron?

Answer 5

-1

Question 6

what is the relative charge of a proton?

Answer 6

+1

Question 7

What does the charge on the nucleus of an atom depend on?

Answer 7

The number of protons in it

Question 8

What are isotopes?

Answer 8

Atoms of an element with different numbers of neutrons

Question 9

what does the ‘12’ refer to in the atom:

carbon-12

Answer 9

the total number of subatomic particles in the nucleus

Question 10

how do you work out the number of neutrons in an atom?

Answer 10

subtract the amount of protons (or atomic number) from the relative atomic mass

Question 11

What do unstable nuclei emit?

Answer 11

Radiation

Question 12

Name two things radiation can be made of

Answer 12

Waves and Particles

Question 13

What do you call materials that emit radiation?

Answer 13

radioactive

Question 14

What is the symbol for an alpha particle?

Answer 14

α

Question 15

what is the symbol of a beta particle

Answer 15

β

Question 16

what is the symbol for a gamma particle?

Answer 16

γ

Question 17

How is radiation detected?

Answer 17

Using a Geiger counter.

device clicks when radiation enters it

Question 18

what is each click in a Geiger-Miller tube?

Answer 18

a tiny current produced when radiation ionises atoms of gas inside the tube

Question 19

List three types of radiation in order from least penetrating to most penetrating.

Answer 19

alpha
beta
gamma

Question 20

What material stops alpha particles?

Answer 20

a few sheets of paper (or cms of air)

Question 21

what material stops beta particles?

Answer 21

a few mm of aluminium

Question 22

what material stops gamma particles?

Answer 22

a few cm of lead (or meter of concrete)

- most gamma is stopped, but some may still pass through!

Question 23

what kind of radiation is emitted by radioactive materials?

and what does it mean?

Answer 23

ionising radiation,

means that the radiation can remove electrons from atoms to produce positively charged ions

Question 24

what is the charge of alpha particles?

Answer 24

+2

Question 25

what is the charge of beta particles?

Answer 25

-1

Question 26

what is the charge of gamma particles?

Answer 26

0

Question 27

why do alpha particles have a shorter range than gamma particles?

Answer 27

because they have high ionising power (transfer more energy to the material that they are travelling through)

Question 28

What happens in alpha decay?

Answer 28

2 protons and 2 neutrons form an alpha particle and leave the nucleus

Question 29

Why does alpha decay occur?

Answer 29

since the atom that they are in have an unstable nuclei

Question 30

Finish off the equation: (alpha decay)

240
Pu —->
94

Answer 30

236 4
U + He
92 2

Question 31

What happens in beta decay?

Answer 31

When a neutron decays and emits an electron. The neutron itself turns into a proton.

Question 32

when does gamma ray decay occur?

Answer 32

when a nucleus usually emits an alpha particle or a beta particle (at the same time)

Question 33

what is a half-life of a radioactive material?

Answer 33

the time it takes for half the unstable nuclei to decay, or for the activity to halve

Question 34

What is the activity/count rate of a radioactive substance measured in?

Answer 34

Becquerels (Bq)

Question 35

Radioactive decay is random. Explain what that means

Answer 35

Random means that an event is equally likely in any time interval.

Question 36

Emission and absorption spectra tell us what about atoms?

Answer 36

Where the electrons are on the atom

Question 37

How many isotopes will be left after 4 weeks if the original sample had 100 atoms? Half-life of the isotope in question = 7 days

Answer 37

7