4.1. Atomic structure

Question 1

what happens when beta decay occurs

Answer 1

A neutron in the nucleus turns into a proton and releases a fast moving electron

Question 2

hazards of contamination

Answer 2

if a radioactive source gets into the human body, the internal organs will be irradiated as the source moves through the body

Question 3

examples of radiation emanating from natural sources

Answer 3

rocks, foods, cosmic rays

Question 4

How to work out the activity of a substance after a period of time

Answer 4

Activity = initial reactivity * 1/2^number of half lives

Question 5

activity

Answer 5

the rate at which the unstable nuclei from a source of radiation decays

Question 6

Alpha particles can be stopped by

Answer 6

paper

Question 7

alpha particles range in air

Answer 7

A few centimetres

Question 8

beta particles range in air

Answer 8

few metres

Question 9

gamma rays range in air

Answer 9

long distance

Question 10

when an atom emits an alpha particle

Answer 10

It’s atomic number reduces by 2 and its mass number reduces by 4

Question 11

what is half life

Answer 11

time taken for half the nuclei of a radioactive substance to decay

Question 12

how to calculate the half life of a substance

Answer 12

calculate the number of half lives, put it to the power of (1/2)^n, find the ratio

Question 13

contamination

Answer 13

the unwanted presence of materials containing radioactive atoms on other materials

Question 14

irradiation

Answer 14

the process of exposing a material to alpha, beta or gamma radiation

Question 15

what is background radiation

Answer 15

The radiation that exists around us all the time

Question 16

two types of background radiation

Answer 16

natural sources, man-made sources

Question 17

examples of man-made sources of radiation

Answer 17

nuclear weapons testing, medical testing

Question 18

what is the danger with a long half life

Answer 18

a substance with a long half life will remain radioactive for a very long time, so it is buried underground to prevent it from being released into the environment

Question 19

medical uses of radiation

Answer 19

tracers-track the movement of substances around the body
radiotherapy-treat cancer

Question 20

describe the process of nuclear fission

Answer 20

• a neutron is absorbed by a large nucleus
• the nucleus splits into two smaller nuclei
• releasing energy and gamma rays
• and two / three neutrons

Question 21

what is activity measured in

Answer 21

Becquerels (Bq)

Question 22

beta particles can be stopped by

Answer 22

aluminum foil

Question 23

gamma rays can be stopped by

Answer 23

thick lead

Question 24

ionising power of alpha particles

Answer 24

high

Question 25

ionising power of beta particles

Answer 25

moderate

Question 26

ionising power of gamma rays

Answer 26

low

Question 27

what is an alpha particle

Answer 27

2 protons and 2 neutrons

Question 28

what is a beta particle

Answer 28

an electron

Question 29

what is a gamma ray

Answer 29

an electromagnetic wave

Question 30

what happens to the mass of an atom when beta decay occurs

Answer 30

doesnt change

Question 31

who discovered radioactivity

Answer 31

marie curie

Question 32

danger with a short half life

Answer 32

if a large amount is used, the level of radiation emitted could make handling the isotope extremely dangerous

Question 33

what is nuclear fission

Answer 33

the splitting of a large and unstable nucleus into two smaller nuclei

Question 34

what is this diagram an example of

Answer 34

nuclear fission chain reaction

Question 35

what is nuclear fusion

Answer 35

the process of combining lightweight nuclei to make heavier nuclei

Question 36

what is needed for nuclear fusion take place

Answer 36

high temperature

Question 37

How can an electron move up an energy level?

Answer 37

gain energy by absorbing EM radiation

Question 38

advantages of nuclear fission

Answer 38

No Greenhouse Gases High Energy Output Reliable & Long-Lasting

Question 39

disadvantages of nuclear fission

Answer 39

Radioactive Waste Accident Risk High Costs Non-Renewable Fuel

Question 40

advantages of nuclear fusion

Answer 40

Abundant Fuel Less Waste Safer More Energy - potential for a higher energy output than nuclear fission

Question 41

disadvantages of nuclear fusion

Answer 41

Technologically Immature: Extremely difficult to start and sustain the high temperatures/pressures needed. Research Stage: Not yet commercially viable; still experimental. High Energy Input: Current reactors consume significant energy to run.

Question 42

what is a consequence of a nuclear fission uncontrolled chain reaction

Answer 42

an explosion

Question 43

how does nuclear fusion release energy

Answer 43

some of the mass of the two smaller nuclei is converted to energy

Question 44

polonium-209 has a half-life of 125 years. polonium-210 has a half life of 138 days. how does the activity of polonium-209 compare with the activity of polonium-210

Answer 44

The activity of polonium-209 is much lower than polonium-210. This is because polonium-209 has a much longer half-life, so its atoms decay more slowly