Radioactivity

the emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei

radioactivity

Z

atomic number; number of protons in the nucleus

how many protons can you zeeeee

the atomic number (Z) is the number of ___

protons in the nucleus of the atom

A

atomic mass

A for Adding - protons plus neutrons

the atomic mass (A) is the number of ___

number of protons plus neutrons in the nucleus of the atom

A for Adding (protons plus neutrons)

on the periodic table, the atomic number (Z) is the number ___ the chemical symbol and the atomic mass (A) is the number ___ the chemical symbol

atomic number is above, atomic mass is below

how do you calculate the number of neutrons in an atom?

A-Z

atomic mass minus atomic number

isotoPes have the same number of

protons (Z)

different neutrons and atomic mass (A)

isotoNes have the same number of

neutrons

different number of protons (Z) and atomic mass (A)

isobArs have the same number of

atomic mass (A)

different number protons (Z) and neutrons to get there

isomErs have the same number of

everything - protons (Z), neutrons, and atomic mass (A)

what’s different is Energy. it has excess energy (is metastable)

if isomErs have the same numbers of everything (protons, neutrons, atomic mass), what is different?

energy. they have excess energy = metastable

are most elements stable or unstable?

most elements are in a stable state

if an element is unstable, it has ___

too many protons or neutrons. they need to expend energy in order to return to a stable state.

when in atom is unstable, it (the parent) will release a particle through certain decay processes. the resulting atom is called the ___

daughter

5 types of decay processes

alpha decay (2 protons + 2 neutrons bonded=He)

beta minus decay

beta plus decay

electron capture

isomeric transition

how does alpha decay work?

the nucleus of a heavy atom emits an alpha particle (2 protons and 2 neutrons - a helium nucleus)

the resulting daughter now has A-4 and Z-2

a new element is formed

an alpha particle consists of ___

2 protons and 2 neutrons

which is a helium nucleus

why are alpha particles not used for treatment?

they are heavy particles that can be stopped in less than 1 mm of tissue

alpha particles are dangerous when ___

ingested into the digestive or respiratory tracts (radium 226 alpha decays into radioactive radon-86)

2nd leading cause of lung cancer

radon

radon-86 is produced when radium 226 undergoes ___

alpha decay

beta particles are ___ that originate from the ___

electrons; originate from the nucleus rather than orbital shells

a beta-plus particle is a ___ originating from the ___. it is also called the ___.

positive electron; nucleus

anti-particle or anti-matter

other terms for a beta-plus particle

anti-particle or anti-matter

where does a beta-plus particle originate from?

the nucleus

beta-plus decay is generated from what kind of particle? beta-minus decay is generated from what kind of particle?

beta-plus: electron from the nucleus

beta-minus: neutrons converted to a proton/B- pair

how does beta-minus decay happen?

a nucleus with too many neutrons converts a neutron to a proton/B-pair, then expels the B- particle with an energy spurt

the daughter has the same A but Z+1, so becomes a different element

example: P32 becomes S32

in beta-minus decay, a nucleus with too many neutrons converts a ___ to a ___, then expels the ___ with an energy spurt

neutron to a proton/B- pair, then expels the B- particle

in beta-minus decay, the parent has too many ___. in beta-plus decay, the parent has too many ___

beta-minus decay = too many neutrons

beta-Plus decay = too many Protons

in beta-plus decay, the parent converts a ___ into a ___

proton into a neutron/B+ particle (which is expelled)

how does beta-plus decay work?

the parent has too many Protons, not enough neutrons. converts a Proton into a neutron and a B+ particle, which is expelled. daughter has same A, but Z-1, so it becomes a different element. the B+ particle goes on to interact with an electron, and an annihilation occurs, resulting in 2 gamma photons of .511 MeV each (pair production)

a beta-plus particle is also called a ___

positron

what kind of interaction comes from beta-plus decay?

pair production

in beta-plus decay, the B+ particle goes on to interact with an ___, and an ___ occurs, resulting in ___ of ___ MeV each

electron, an annihilation occurs, resulting in 2 gamma photons of .511 MeV each

both beta-minus decay and beta-plus decay will give off some kinetic energy and a ____, an almost massless particle

neutrino

type of decay where an orbiting electron (usually in the K shell) is captured by the nucleus and a proton is replaced by a neutron (characteristic radiation)

electron capture

in electron capture, an orbiting electron (usually in the ___ shell) is captured by the ___ and a ____ is replaced by a ___

K shell; nucleus; proton is replaced by a neutron

what type of radiation is electron capture?

characteristic radiation

I-125 is created by what type of decay?

electron capture

in electron capture, the daughter gains a new ___. a new element is formed because of the loss of a ___.

gains a neutron; new element because of loss of a proton

type of decay where the particles in the nucleus rearrange themselves in order to become stable (nothing is ejected)

isomeric transition

in isomeric transition, the ___ remain the same. the only change is that the atom has ___ that will be given off as ____

A and Z remain the same. atom has excess energy that will be given off as gamma photons (which can be imaged with a gamma camera)

Tehcnetium 99m is used for bone scans. its type of decay is an example of ___

isomeric transition

the m stands for metastable state of Tech-99

the time it takes for radioactivity to decrease/decay to one-half the original intensity

half-life (T ½ )

after one T ½ the activity would be ___%, after 2 T ½ the activity would be ___%, after 3 T ½ the activity would be ___%

50%, 25%, 12.5%

half-life of Cobalt-60

5.26 years