radioactivity

Question 1

what is the atomic number

Answer 1

the number of protons

Question 2

what is the atomic mass number

Answer 2

the number of nucleons

Question 3

how to calculate the number of neutrons

Answer 3

A - Z

Question 4

what is the n:p ratio of most of the first 20 elements

Answer 4

1:1

Question 5

what is the n:p ratio of the elements that z>20

Answer 5

the number of neutrons exceeds the number of protons

Question 6

what happens to the n:p ratio of unstable nuclei

Answer 6

disintegrate to achieve the ideal n:p ratio

Question 7

what is emitted when unstable nuclei disintegrate

Answer 7

radiation and/or fast-moving particles

Question 8

what is an isotope

Answer 8

atom with the same number of protons but a different number of neutrons

Question 9

what is a radioisotope

Answer 9

an unstable isotope

Question 10

at what element does the belt of stability end

Answer 10

83 bismuth

Question 11

all elements with ___ protons or more are ___

Answer 11

84, radioactive

Question 12

what is the red line on the nuclear belt of stability

Answer 12

n:p = 1

Question 13

Z = 1-20
stable N/Z = ?

Answer 13

1

Question 14

Z = 20-40
stable N/Z = ?

Answer 14

approaches 1.25

Question 15

Z = 40-83
stable N/Z = ?

Answer 15

approaches 1.5

Question 16

what is the law of the conservation of matter

Answer 16

matter is never created nor destroyed

Question 17

what is the formula of the format of a reaction

Answer 17

X = R + Y

Question 18

alpha decay happens with what type of particles

Answer 18

heavy and unstable nuclei

Question 19

why does alpha decay happen

Answer 19

nucleus is too large to balance the forces

Question 20

alpha particles have __ protons and __ neutrons

Answer 20

2 and 2

Question 21

what are the 4 alpha particle properties

Answer 21

• heaviest of emissions
• positive charge
• highly ionizing
• very short range

Question 22

how far can alpha particles travel? In air and soft tissue

Answer 22

1-10 cm in air
0,1 mm in soft tissue

Question 23

in what type of molecules does beta - emission happen

Answer 23

neutron rich nuclei

Question 24

what is the b- symbol

Answer 24

^0, -1, b-

Question 25

why does b- emission occur

Answer 25

n"p is too high

Question 26

what is the solution of the b- emission

Answer 26

neutrons dec by 1 protons inc by 1 lower n:p

Question 27

what are 4 beta- particle properties

Answer 27

- identical to electron - negative charge - ionizing - short range

Question 28

in what type of molecules does b+ emission happen

Answer 28

proton rich nuclei

Question 29

why does b_ emission happen

Answer 29

too many protons n:p too low

Question 30

what is the solution of b+

Answer 30

give off radiation that reduces Z, or inc n

Question 31

what are the 2 properties of b+ emission particles

Answer 31

positive electric charge ionizing

Question 32

when b+ eparticles combine with electrons, it is called ___

Answer 32

an annihilation reaction

Question 33

if n:z ratio is too high, what happens

Answer 33

neutrons are converted to protons via beta decay

Question 34

if n:z is too low, what happens

Answer 34

protons are converted to neutrons via positrons emission

Question 35

if amu is too high, hwhat happens

Answer 35

alpha decay (change to both n and p )

Question 36

what is an isometric reaction

Answer 36

nucleus may be excited following emission can release energy wo changing p or n

Question 37

what is typically released in an isometric reaction

Answer 37

gamma rays

Question 38

does gamma emission affect the n:z ratio

Answer 38

no

Question 39

what are the properties of gamma emission (3)

Answer 39

- no charge or mass - ionizing - highly penetrating

Question 40

absorbed dose = ?

Answer 40

energy absorbed per unit mass of tissue

Question 41

equivalent dose = ?

Answer 41

absorbed dose x radiation weighting factor

Question 42

effective dose = ?

Answer 42

equivalent dose x tissue weighting factor

Question 43

what has a weighting factor of 1

Answer 43

photons, electrons

Question 44

what has a weighting factor of 2

Answer 44

protons

Question 45

what has a weighting factor of 2-

Answer 45

alpha particles, heavy ions

Question 46

what is LET

Answer 46

linear energy transfer avg E deposited per unit length

Question 47

what is the unit for LET

Answer 47

linear energy transfer keV / mu m

Question 48

which particles have high LET

Answer 48

alpha parivles protons neutrons

Question 49

which particles have lower LET

Answer 49

electrons positrons gamma rays xrays

Question 50

what is the threshold number for high/low LET

Answer 50

3 keV/mum

Question 51

what is activity (A)

Answer 51

number of radioactive decays per second

Question 52

what is the unit for radioactive activity

Answer 52

Bq - bequerel one transformation/decay per second

Question 53

high actovoty = (high/low) radioactivoty

Answer 53

high

Question 54

what does activity depend on

Answer 54

1. amount of substance 2, half life of substance

Question 55

longer half life = (higher / lower) activity

Answer 55

lower

Question 56

A (t) = ?

Answer 56

A0 (e^-dc t)

Question 57

N(t) =

Answer 57

N0 (e^-dct)

Question 58

what is the decay constant

Answer 58

rate at which the radionuclide decays

Question 59

why are isotopes with short half lives useful (3)

Answer 59

- cheap to make - less does to pt and staff - post treatment activity is low