Radioactivity

Question 1

What does a particle contain

Answer 1

Protons Neutrons Electrons

Question 2

What charge does each particles have

Answer 2

e=- pro= + neut= neutral

Question 3

What prbit around the nucleus?

Answer 3

electrons

Question 4

How can electrons move between energy levels?

Answer 4

electrons can move up energy levels by absorbing energy

down by releasing energy

Question 5

all matter is made from (1)
the element copper is a metal that is just made from (2) atoms
an attom has a (3) whihc contains (4)
negativley charged particle called (5) orbit around the (6)
atoms have no overall charge so they are said to be (7)

Answer 5

1
atoms
2
copper
3
nucleus
4
protons
7
electrons
6
nucleus
7
neutral

Question 6

the relative charge and relative mass of Protons, Neutrons and electrons

Answer 6

p
rc= +1
rm = 1
N
rc=0
rm=1
E
rc=-1
rm=0

Question 7

What is atomic mass

Answer 7

top number
#protons and neutrons in nucleus
(#particles in nucleus)

Question 8

what is the Atomic number

Answer 8

#of protons in nucleus
#p=#e

Question 9

define Isotope

Answer 9

the atoms of a element with diffrent numbers of neutrons. they have the same proton number but diffrent mass numbers

Question 10

Why are some isotopes radioactive?

Answer 10

their neutron/proton ratio are too large/small

Question 11

What determines an nucleus’ stability

Answer 11

n/p ration

Question 12

what happends when a nucleus has a too large or too small n/p?

Answer 12

unstable

decays to form a more stable nucleus

Question 13

how does an unstable isotope decay

Answer 13

emits radiation to form a more stable isotope (radioactiviy)

Question 14

Why are some nuclei radioactive?

Answer 14

radioactivity
the property possesed by unstable elements of spontaneously emmiting energetic particles (beta/alpha) by the decay of their atomic nuclei on order to becom stable

Question 15

how do unstable nuclei become stable

Answer 15

releasing particles from their nucleus in order to change the p/n

Question 16

3 types of radiation

Answer 16

alpha
beta
gama

Question 17

what is alpha radiation

Answer 17

a helium nucleus
2 p
2 n
stopped by paper or a few cm of air
strongly ionising
weakly deflected

Question 18

what is a beta ionising radiation

Answer 18

high energy electron
stopped by thin aluminium
weakly inoising
strongly deflected

Question 19

what is gamma ionising radiation

Answer 19

an em wave (left over energy)
REDUCED by several cm of lead of meters of concrete
very weakly ionising
no deflection

Question 20

what do alpha,beta and gamma do to an atom

Answer 20

pull electrons away from atoms

Question 21

describe the use of radiation in smoke detectors

Answer 21

alpha
source pass to detector
smoke stops alpha partices reaching detector
alarm sounds

since very ionising / least penetrating
its stopped by smoke particles

Question 22

describe the use of beta in thickness of paper

Answer 22

beta source passes through paper
amount of particles detected on other side
too few pass through = paper to thik, roller pressure increase
too many pass through paper = paper thin, roller preassure decreased

Question 23

describe the role of gamma in leaks in pipes

Answer 23

radioactive isotop injected into pipe
detector is moved along the ground above the pipe
leak is located where theres an increase in activity and little or no activity after this point

Question 24

describe alpha decay

Answer 24

when an alpha particle is emmited from a nucleus, the nucleus loses 2 protons and 3 neutrons
meaning mass # decreases by 4 and atomic # decreases by 2

Question 25

What are the constants in alpha decay

Answer 25

``` mass decrease by 4 # decrease by 2 ```

Question 26

describe beta decay

Answer 26

beta perticle = electron emited from nucleus occurs when: too many protons, neutrons one of protons or neutrons = transformed into other in beta minus decay, a neutron decays into a ptroton releasing an lectron

Question 27

describe nuclei decay

Answer 27

completley random. heating up source/cooling it down/squashing it/ breaking it up etc. has no efects matter of probability

Question 28

define half life

Answer 28

time it takes for the # of nuclei of the isotope in a sample to 1/2 time it takes for the count rate from sample containing the isotope to fall to half of its starting level

Question 29

what is background radiation

Answer 29

exposure to a certain amount of nuclear radiation every day

Question 30

list the medical uses of nuclear radiation

Answer 30

cancer treatment imaging tracers

Question 31

how does a medical tracer work

Answer 31

half life 66 hrs short half life and decays before it can do much damage long enough to pass through body and be detected decays into stable isotope

Question 32

how does a gamma camera work

Answer 32

allows radiologists to carry out tests providing detailed diagnostics about functioning of the thyroid, heat, lungs etc. half life 66 hrs short hal life and decays before much damage is done long enough to pass thorugh body detected decays into stable isotope

Question 33

how does a gamma knife work

Answer 33

gives you high doses of radiation targeted to reach very small part of brain so it doesnt damage surrounding healthy tisues half life 5.7 years doesnt remain in body so half life doesnt matter relativley stable, will not decay before it is used

Question 34

how does radiotherapy work

Answer 34

high dose of gamma directed to kill cancerous cellls from outside using x rays from radioactive cobalt from inside by putting radioactive material into tumor or close to it half life 5.7 years doesnt remain in body so half life doesnt matter'relatively stable wont decay before its used

Question 35

describe a radioactive implant

Answer 35

small radioacltive source placed directly on tumor | small dose of gamma is given over a long period of time directly into the tumor (killing cells)

Question 36

what is the diffrence between a nuclear reactor and a nuclear bomb

Answer 36

nuclear power and nuclear bombs usually use a radioactive source (uranium usually) both radioactive source under go fission to produce energy, but one explodes and the other doesent

Question 37

describe nuclear power

Answer 37

energy is released in a nuclear reactor because of nuclear fission

Question 38

3 types of fission

Answer 38

``` nuclear - unstable nuclei splits toform 2 smaller nuclei spontaneous - rare induced ```

Question 39

descrube the fission process

Answer 39

neutron travels at high speed towards a nucleus neutron strikes nucleus and captures a neutron nucleus = unstable transforms into elpngated shape for short time splits into 2 fission fragments and releases neutrons

Question 40

how does fission relase energy

Answer 40

KE of products pf fissionare far greater than that of a bombarding neutron and target atoms this enery is released as heat and used in nucclear reactors

Question 41

what is thermonuclear fusion

Answer 41

nucleasr FUSION occurs when nuclei are fused togather generates heat energy product aren't radioactive