T4 - Atomic structure

Question 1

Radius of atom?

Answer 1

1 × 10^-10m

Question 2

Radius of nucleus?

Answer 2

1 x 10^-14m

Question 3

Which electrons shell have higher energy?

Answer 3

electron shell further from nucleus

Question 4

What happens to electron when atom absorbs electromagnetic radiation?

Answer 4

moves to high electron shell

Question 5

What happens to electron when atom emits electromagnetic radiation?

Answer 5

moves to lower electron shell

Question 6

What is an isotope?

Answer 6

Atoms of the same element that have different numbers of neutrons

Question 7

What is radioactive decay?

Answer 7

when the nucleus gives out radiation to become more stable

Question 8

Feature of radioactive decay?

Answer 8

its a random process

Question 9

What is activity?

Answer 9

rate at which a source of unstable nuclei decay

Question 10

What is activity measured in?

Answer 10

becquerel(Bq)

Question 11

What is the count rate?

Answer 11

the number of decays recorded each second by a detector

Question 12

Types of radiation? x4

Answer 12

-alpha particle
-beta particle
-gamma ray
-neutrom

Question 13

What is an alpha particle?

Answer 13

two neutrons and two protons

Question 14

which nucleus is the alpha particle same as?

Answer 14

helium nucleus

Question 15

What is a beta particle?

Answer 15

a high speed electron ejected from the nucleus as a neutron turns into a proton

Question 16

What is a gamma ray?

Answer 16

electromagnetic radiation from the nucleus

Question 17

How far can alpha paricles travel?

Answer 17

5cm

Question 18

How far can beta paricles travel?

Answer 18

15cm

Question 19

How far can gamma rays travel?

Answer 19

several metres

Question 20

What are alpha particles stopped by?

Answer 20

a sheet of paper

Question 21

What are beta particles stopped by?

Answer 21

few millimetres of aluminium

Question 22

What are gamma rays stopped by?

Answer 22

several centimetres of lead

Question 23

Ionising power of alpha particles?

Answer 23

very strongly ionising

Question 24

Ionising power of beta particles?

Answer 24

quite strongly ionising

Question 25

Ionising power of gamma rays?

Answer 25

weakly ionising

Question 26

What is ionising power?

Answer 26

when atoms loose electrons and form ions when collided with radiation

Question 27

What happens to atomic number during alpha decay?

Answer 27

decreases by 2

Question 28

What happens to the mass number during alpha decay?

Answer 28

decreases by 4

Question 29

What happens to atomic number during beta decay?

Answer 29

increases by 1

Question 30

What happens to mass number during beta decay?

Answer 30

stays the same

Question 31

What happens to the mass and atomic number during gamma decay?

Answer 31

stays the same

Question 32

What is half life?

Answer 32

time it takes for the number of nuclei of the isotope or count rate in a sample to halve

Question 33

What is irradiation?

Answer 33

exposing an object to nuclear radiation

Question 34

What happens to the object getting irradiated?

Answer 34

it doesn't become radioactive

Question 35

Why doesn't an object getting irradiated become radioactive?

Answer 35

doesnt come in contact with radioactive isotope

Question 36

Why is ionising radiation dangerous?

Answer 36

increase risk of cancer

Question 37

What are the precautions that can be taken to when working with radioactive isotopes? x2

Answer 37

- shielding -monotoring

Question 38

How to take precaution of alpha radiation by shielding?

Answer 38

gloves

Question 39

How to take precaution of beta and gamma radiation by shielding?

Answer 39

lead apron

Question 40

What is radioactive contamination?

Answer 40

when unwanted radioactive isotopes end up on other materials

Question 41

Why are affect of radiation on humans published and shared with other scientists?

Answer 41

so it can be peer reviewed

Question 42

where does natural background radiation come from? x2

Answer 42

-rocks -cosmic rays

Question 43

where does man made background radiation come from? x2

Answer 43

-nuclear weapon testing -nuclear accidents

Question 44

What can affect your exposure to background radiation? x2

Answer 44

-occupation -location

Question 45

Uses of nuclear radiation in medicine? x2

Answer 45

-exploring internal organs -control or destroy unwanted tissue

Question 46

How can nuclear radiation help explore internal organs- thyroid gland?

Answer 46

radioactive iodine drank to see condition of thyroid gland

Question 47

How can nuclear radiation help explore internal organs-tumours?

Answer 47

tracers

Question 48

Issues of tracers? x4

Answer 48

-radiation must pass out of body -not strongly ionising -not decay into radioactive isotope -must have short half life

Question 49

How can nuclear radiation destroy unwanted tissue? x2

Answer 49

-radiotherapy -radioactive rods

Question 50

Issues of radiotherapy?

Answer 50

healthy tissue can be destroyed

Question 51

What is nuclear fission?

Answer 51

splitting of large and unstable nucleus

Question 52

What must happen to unstable nucleus for fission to occur?

Answer 52

absorb neutron

Question 53

process of nuclear fission? x3

Answer 53

1. unstable nucleus absorb neutron 2. nucleus splits to 2 3. emits 2 or 3 neutrons and gamma rays

Question 54

What is released by fission?

Answer 54

energy

Question 55

what do all fission products have?

Answer 55

kinetic energy

Question 56

What is a chain reaction?

Answer 56

repetition of nuclear fission

Question 57

What is a chain reaction is controlled in?

Answer 57

nuclear reactor

Question 58

Why is chain reaction controlled in a nuclear reactor?

Answer 58

to control energy released

Question 59

what is a nuclear weapon explosion caused by?

Answer 59

uncontrolled chain reaction

Question 60

What is nuclear fussion?

Answer 60

joining of two light nuclei to form a heavier nucleus

Question 61

What happens to some of the mass of nuclei during nuclear fusion?

Answer 61

converted into energy of radiation