Nature of Atomic Radiations Flashcards
START of exam 2 material
anything that has mass and occupies space
matter
two types of models for atoms
classical, standard
nucleus characteristics
- composed of P and N
- 99.998% of mass
- net positive charge
orbital electrons characteristics
- 0.002% of mass
- net negative charge
atoms with single nucleus, with 0 neutrons
Hydrogen (H)
larger atom/element, 74 protons in nucleus
Tungsten (W)
Z-number is the…
atomic number (proton number)
Z-number tells number of protons and ____ (net ___ charge)
electrons, neutral
atomic mass number =
protons + neutrons
A-number is the…
atomic mass number
***elements with different numbers of neutrons but the same number of protons
isotopes
orbitals differ in the ______ from the nucleus
distance and energy
inner orbitals are ____ tightly bound than outer orbitals
more
higher the _____ the higher the binding energy for any particular orbital
Z #
formation of an ion pair
ionization
isotopes
same _____
different ___
same protons; different neutrons
how many isotopes does H have?
3
how many isotopes does C have? Which is most common?
6, 6C12 (“carbon 12”)
too many or too few neutrons make nuclide unstable or _____
radioactive
neutrons ____ protons
stabilize
nuclei of radioactive isotopes
radionuclides
why are radioactive isotopes unstable?
imbalance in number between protons and neutrons
to become stable, radionuclides eject _____ and _____
particles (P, N, alpha, beta) and EM radiation (gamma radiation)
ejection of particles and radiation
radioactivity
process of energy ejection
nuclear disintegration
nuclear disintegration continues until ___ is achieved
stability
time after which the activity decays to half its original value
half-life
half-life never really becomes zero, it just becomes ____
very, very small
measuring half-life applies from ____
any starting point
Tc99 half-life
6 hours
If a radioactive material with 100 Bq of activity and a half life of 1 hour, how much activity will remain in 3 hours?
100 > 50 (1 half life)
50 > 25 (2 half lives)
25 > 12.5 (3 half lives)
12.5 Bq
energy acquired by an e- when it passes through an electrical potential difference of one volt
electron volt (eV)
eV ultimately influences ___
x-ray beam
transfer of energy through space and matter
radiations
two types of radiation
- particulate radiation
- Electromagnetic radiation
transfer of energy by high velocity subatomic particulates
particulate radiation
energy of particulate radiation is ____
kinetic energy
increase ______, increase kinetic energy
mass of particle
increase velocity of particle, ____
increase kinetic energy
rate of loss of energy as a particle moves through an absorber
linear energy transfer (LET)
increase mass of particle, ____
increase LET
increase charge of particle, ____
increase LET
increase velocity of particle, ______
decrease LET
increase chemical composition (Z #), thickness, or density of absorber, ______
increase LET
non-particulate radiation includes
entire electromagnetic spectrum
two theories of EMR
- wave theory
- quantum theory
wavelength measured ____
between crests/troughs
number of oscillations, vibrations, “waves”, or cycles per ____
frequency, per second
c = (lambda)(velocity) describes relationship between…
- velocity
- frequency
- wavelength
increase frequency, ___ of EMR
increase energy
decrease frequency, _______ of EMR
decrease energy
increase wavelength, ______ of EMR
decrease energy
decrease wavelength, _____ of EMR
increase energy
ranking of EMRs in order of decreasing energy
gamma rays, x-rays, UV rays, visible light, infrared, microwave, radio
red light is…
longest wavelength, lowest energy
violet light is…
shortest wavelength, highest energy
dental x-rays use…
polychromatic beam
