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

What do you call materials that emit radiation?

Answer 12

radioactive

Question 13

What is the symbol for an alpha particle?

Answer 13

α

Question 14

what is the symbol of a beta particle

Answer 14

β

Question 15

what is the symbol for a gamma particle?

Answer 15

γ

Question 16

How is radiation detected?

Answer 16

Using a Geiger counter.

device clicks when radiation enters it

Question 17

what is each click in a Geiger-Miller tube?

Answer 17

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

Question 18

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

Answer 18

alpha
beta
gamma

Question 19

What material stops alpha particles?

Answer 19

a few sheets of paper

Question 20

what material stops beta particles?

Answer 20

a few mm of aluminium

Question 21

what material stops gamma particles?

Answer 21

a few cm of lead (or m of concrete)

Question 22

what kind of radiation is emitted by radioactive materials?

and what does it mean?

Answer 22

ionising radiation,

means that the radiation can remove electrons from atoms or give electrons to atoms to produce ions

Question 23

what is the charge of alpha particles?

Answer 23

+2

Question 24

what is the charge of beta particles?

Answer 24

-1

Question 25

what is the charge of gamma particles?

Answer 25

0

Question 26

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

Answer 26

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

Question 27

What happens in alpha decay?

Answer 27

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

Question 28

Why does alpha decay occur?

Answer 28

since the atom that they are in have an unstable nuclei (too many protons)

Question 29

Finish off the equation: (alpha decay) 240 Pu —-> 94

Answer 29

236 4 U + He 92 2

Question 30

What happens in beta decay?

Answer 30

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

Question 31

when does gamma ray decay occur?

Answer 31

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

Question 32

what is a half-life of a radioactive material?

Answer 32

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

Question 33

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

Answer 33

Becquerels (Bq)

Question 34

Radioactive decay is random. Explain what that means

Answer 34

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

Question 35

Emission and absorption spectra tell us what about atoms?

Answer 35

Where the electrons are on the atom

Question 36

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

Answer 36

~6 (6.25)