atomic structure physics

Question 1

what is alpha radiation and how is it made?

Answer 1

a helium nuclei / 2 protons + 2 neutrons
when an alpha particle is emitted from the nucleus, 2 neutrons + 2 protons

Question 2

what is beta radiation and how is it made?

Answer 2

high-speed electron
a neutron is turned into a proton and an electron
a fast moving electron is released/ ejected by the nucleus

Question 3

what is gamma radiation and how is it made?

Answer 3

EM waves / high energy wave / high frequency / short wavelength
waves of electromagnetic radiation released by the nucleus, when nucleus changes shape

Question 4

write alpha, beta and gamma in the order of starting with the most penetrating to the least

Answer 4

gamma (penetrate far)
beta (moderately penetrating)
alpha (doesn’t penetrate far)

Question 5

what can alpha, beta and gamma be stopped by?

Answer 5

alpha: sheet of paper, a few cm of air, skin
beta: a sheet of aluminium, few sheets of paper
gamma: thick sheets of lead, metres of concrete

Question 6

what happens when radiation ionises?

Answer 6

radiation ionises and that is what makes the dangerous for living organisms. It damages DNA, kills cells and causes cancer

Question 7

uses of alpha, beta and gamma radiation

Answer 7

alpha ~ smoke alarms
beta ~ paper mills, controls thickness of paper
gamma ~ sterilising equipment

Question 8

what do nuclear equations show?

Answer 8

radioactive decay

Question 9

what is the mass and the atomic number of an alpha particle?

Answer 9

mass: 4
atomic number: 2

Question 10

what is the mass and atomic number for beta?

Answer 10

mass: 0
atomic number: -1

Question 11

define half life

Answer 11

half life is the time taken for the radioactive nuclei to decay to become stable

Question 12

what is background radiation?

Answer 12

background radiation is the low-level radiation that is a around us all the time

Question 13

what are natural sources of background radiation?

Answer 13

radioactive rock
cosmic rays
food + drink

Question 14

what are the man-made sources of background radiation?

Answer 14

nuclear weapons testing
nuclear accidents

Question 15

what is exposure to background radiation affected by?

Answer 15

occupation and location

Question 16

What are doses of radiation measured in?

Answer 16

sieverts (Sv)
1 Sv = 1000 mSv

Question 17

What does the radiation dose tell you?

Answer 17

Radiation dose tells you the risk of harm to the body tissues due to exposing of radiation

Question 18

what is irradiation?

Answer 18

exposes you to radiation

Question 19

what is contamination radiation?

Answer 19

radiation gets onto or into an object

Question 20

what determines how harmful radiation is?

Answer 20

how far away from the source you are
how long you’re exposed
how radioactive the substance is

Question 21

what are the precautions to minimise contamination?

Answer 21

gloves
tongs
overalls

Question 22

can you emit radiation to others when exposed to radiation?

Answer 22

no
you can’t emit radiation to others when exposed to radiation

Question 23

what is radiotherapy used for?

Answer 23

can be used to treat cancer

ionising radiation will kill all living cells
gamma rays are directed carefully and at just the right dosage to kill the cancer cells, without damaging too many normal cells

Question 24

what are the dangers or risks of radiotherapy?

Answer 24

a bit of damage is inevitably done to normal cells, which makes the patient feel very ill

Question 25

what are medical tracers used for?

Answer 25

certain radioactive isotopes can be injected into people and their progress around the body can be followed using an external detector

Question 26

what are the dangers and risks of medical tracers?

Answer 26

risk of cancer from one use of tracer is very small
side effects
can make you feel ill

Question 27

what are the ideal properties of medical tracers?

Answer 27

short half life ~ minimises external damage to cells
most penetrating ~ gamma (never alpha)
low ionising power ~ less damage to cells

Question 28

what are the hazards of radioactive sources?

Answer 28

Radioactive sources can damage or cause cells to mutate when exposed + cancer

Question 29

What is the instrument that measures radiation?

Answer 29

geiger counter
(counts the count rate)

Question 30

what is nuclear fission?

Answer 30

the splitting of large and unstable nucleus. NOT AN ATOM!!

Question 31

what is the method for nuclear fission?

Answer 31

a chain reaction
a neutron is absorbed by an unstable nucleus
nucleus undergoes fission splits into two smaller nuclei
this releases lots of energy and Gamma radiation
2 or 3 neutrons are also released

Question 32

what process is radioactivity?

Answer 32

radioactivity is a totally random process meaning you can’t predict exactly which nucleus in a sample will decay next, or when one of them will decay

Question 33

what are ways to reduce irradiation?

Answer 33

keeping sources in lead-lined boxes
standing behind barriers
being in a different room
using remote-controlled arms

Question 34

what is nuclear fusion

Answer 34

Nuclear fusion is where two small, light nuclei collide at high speed and join together to make one heavy nucleus

Question 35

define half life

Answer 35

half life is the time taken for a radioactive nuclei to decay and become stable

Question 36

what is an isotope?

Answer 36

atoms with the same number of protons and electrons but have a different number of neutrons

Question 37

what is ionisation?

Answer 37

when an atom loses or gains electrons

Question 38

what is the activity of a source?

Answer 38

when the half-life can be used to find the rate at which a source decays - it’s ACTIVITY