P4 atomic structure

Question 1

Structure of atom

Answer 1

Nucleus has protons and neutrons

Electrons surround nucleus in shells

Question 2

Isotopes

Answer 2

An element that has Same number of protons but different number of neutrons

Question 3

A
X
Z

Answer 3

A- mass number (nucleons number)
Z- atomic number (proton number)
X- chemical symbol for the element
Neutrons is A-Z

Question 4

Ionised

Answer 4

Then an atom gains or loses electrons

Question 5

Energy levels

Answer 5

Electrons occupy the space around the nucleus at a specific distance
Electrons can move levels/shells

Question 6

Radioisotope

Answer 6

An atom with an unstable nucleus

Question 7

Activity of radioisotopes

Answer 7

Number of nuclear delays each second
Measured in becquerels (Bq)
1Bq is 1 count per second

Question 8

Radioactivity

Answer 8

Random process

Not possible to predict when nucleus will decay

Question 9

Radioactive decay

Answer 9

Produces nuclear radiation- radiation emitted from the nucleus
May be alpha, beta particles or gamma ray or a neutron

Question 10

Neutron radiation

Answer 10

Release of a high speed neutron from the nucleus, either from the nucleus or a radioactive atom or the result of nuclear fission

Question 11

Alpha decay

Answer 11

Alpha particle is emitted from nucleus 
Has helium nucleus 2 protons 2 neutrons
Atomic number decreases by 2
Mass number decreases by 4
4
 a
2

Question 12

Beta decay

Answer 12

A neutron decays into proton and electron 
Electron emitted as beta particle 
Atomic number increases by 1
Mass number is the same
0
  B
-1

Question 13

Gamma decay

Answer 13

Gamma rays emitted from nucleus
Very high electromagnetic waves
No charge or mass
Doesn’t affect mass or charge of nucleus

Question 14

Background radiation

Answer 14

Ionising radiation that is around us all the time

Question 15

Background radiation comes from

Answer 15

Natural sources eg. Rocks- granite & cosmic rays from space
Waste products from hospitals
Waste products from nuclear power stations and other industries
X-ray and manufactured radioisotopes used in medical procedures
Small amount from nuclear weapon testing & nuclear accidents
Amount of radiation depends on are you live and job you have

Question 16

Penetrating power

Answer 16

Alpha has least
Beta
Gamma has the most

Question 17

Ionising power

Answer 17

Gamma has the least
Beta
Alpha has the most

Question 18

Half life

Answer 18

The average time it takes for half the nuclei present to decay
Or the time it takes for the activity to fall to half its initial level

Question 19

Radioactive contamination

Answer 19

The unwanted presence of materials containing radioactive atoms.
Can be on surfaces/within solids,liquids,gases (incl. human body)

Question 20

Contamination occurs when…

Answer 20

People swallow or breathe in radioactive materials
Can enter body through open wound or absorbed by skin
Can cause cancer or mutated genes

Question 21

Level of contamination depends on

Answer 21

Penetrating power
Ionising power
Half life of radio isotope

Question 22

Medical tracer

Answer 22

A radioisotope the is put into the body, by injecting or eating

Question 23

Uses of medical tracers

Answer 23

Monitor functioning of internal organs

Check for blockage in a pettiness blood vessel

Question 24

Irradiation

Answer 24

Where an object is exposed to nuclear radiation

Exposure can originate from various sources such as natural sources and background radiation

Question 25

Sources we are irradiated from

Answer 25

Sky- 400000 cosmic rays pass through us per hour Air- 30000 atoms of radioactive gases are breathed in and disintegrate into our lungs per hour Food- 15 million potassium-40 atoms disintegrate into our bodies per hour Soil & building materials- +200million gamma rays pass through us per hour

Question 26

Irradiation uses

Answer 26

sterilise food in hospitals Therapeutic purposes Supermarkets to kill bacteria on fresh food

Question 27

Effects of irradiation

Answer 27

Cell death Accurate repair Misrepair causing mutation

Question 28

Electromagnetic spectrum

Answer 28

``` Radio waves Microwaves Infrared radiation Visible light Ultraviolet X-rays Gamma rays ```

Question 29

Radioisotopes used in medicine must

Answer 29

Mainly emit gamma rays Have suitable half life Not toxic to humans

Question 30

Radiotherapy

Answer 30

Cancer cells can be destroyed by exposing the affected area of the body to extremely large amounts of radiation Nuclear radiation is used to destroy or control unwanted tissue

Question 31

X-rays are preferred to gamma rays because

Answer 31

Produced when needed Rate of production can be controlled Energy can be changed Can not change rate or energy of gamma rays

Question 32

How to protect healthy tissue

Answer 32

Source is slowly rotated around the patient with the tumour at the centre of the circle Source is used in 3 different directions around the target area

Question 33

Brachytherapy

Answer 33

Small sealed radioactive source or seed is placed in tumour Treat cancer in prostate gland, cervix and womb Sometimes additionally used to external radiotherapy

Question 34

Cancer treatment side effects

Answer 34

Vomitting Reddening and pain in the skin like sunburn Greater risk of infection Tiredness

Question 35

Benefits of nuclear radiation

Answer 35

Explore internal organs Destroying or controlling unwanted tissue Tracers used Health of patient

Question 36

Radiation dose

Answer 36

Measure of harm that the treatment can give you Measured in millisieverts (mSv) Max radiation dose in a year is 20mSv

Question 37

Nuclear fission

Answer 37

When a large and unstable nucleus splits with the release of lots of energy Unstable nucleus absorbs neutron splits into 2 daughter nuclei emitting kinetic energy and gamma rays and a neutron This causes a chain reaction

Question 38

Nuclear power station

Answer 38

Fission Has fuel rods which contain radioactive material Control rods are put between fuel rods to absorb neutrons so process isn't as quick

Question 39

Nuclear fusion

Answer 39

The joining of small nuclei such as hydrogen and helium to form a heavier nucleus Energy source for stars like the sun Creates lots of thermal energy Hydrogen fuse at extremely high pressures and temp 10mill degrees No waste products and easy to obtain hydrogen from sea

Question 40

Fusion bombs

Answer 40

1952 Stated with fission reaction Creating high temp for fusion reaction More powerful than atomic bombs