Radiation Flashcards
what symbol stands for atomic number
Z
Z is the number of what in a nucleus
protons
what is the symbol for atomic mass number
A
what does it mean by energy quantisation
total energy of an electron in bound state is quantised
what is energy level
electron bound to an atomic nucleus
what is ground state
energy with lowest energy (most tightly bound) - electrons will always be here
what is excited state
state with energy higher than the ground state
what two things doe photons have
energy and momentum
photons have 0 rest mass how can they have non-zero momentum/ KE
- travel at speed of light
- slightly different rules
electrons lose energy to jump to lower/higher energy level
lower
electrons gain energy to jump to lower/higher energy level
higher
electron cant make a transition to higher or lower energy state with out what
absorbing or emitting radiation
what is the equation for energy of the absorbed or emitted photons
E=hf
what is joule defined in terms of
Macroscopic masses
instead of gravity what do we use to define the electron volt unit
electrostatic potential energy
what is the equation for electrostatic potential energy in an electric field
U=qV
deBroglie’s insight indicated we should treat electrons as ____ rather than small “billiard balls” of matter
- what does this break down
waves
breaks down the solar system model of the atom
quantised energy levels in atomic systems is when election wave-function does what after on circuit of the orbital
matched up perfectly
the number of an electrons and there arrangement into energy levels is called what
electron configuration
a nucelar consituent - either proton or neutron
nucleon
another name for a nucleus, or an atom with specific nuclear makeup
nuclide
atoms with same number of protons - but different neutrons
isotops
atoms with same number of neutrons but different number of protons
isotones
wha is the unit for atomic mass unit
kg
avogardo’s number is the number of atoms in excatly ____ of carbon 12
0.012kg
converting atomic mass unit into energy using what calculation
E=mc^2
strong nuclear force is what range, type of force, and acts like what
short range
residual force
acts like glue
what does a residual force do
binds protons to protons
and protons to neutrons
what is the drop of liquid analogy
nucleus is like a drop of charged liquid
- to turn liquid into gas need some energy
- then energy is latent heat of vaporisation
if we wanted to break the atom into its constituent parts what energy do we need
binding energy
the greater bindig energy , more energy have to break it apart means what to the atom
the more stabalised atom is
the joining together of smaller nuclei to form larger more stable nuclei
- elements with mass number <56
- high temp
fussion
breaking up of larger nuclei to form smaller nuclei
= mass number >56
= produce energy
fission
radiation is the product of ______ _____
nuclear decay
when nucleus decays what happens to the atomic number (Z)
- and what happens when this occurs
may change
- atom transforms from one element to another
all elements z> ___ are radioactive
82
what are the three types of radiation
alpha, beta, gamma
alpha particles are helium nuclei what does this mean
two protons and two neutrons - because helium is number 2 on the periodic table
what are beta particles made out of
electrons or positrons
what charge is beta radiation
- (electronic ) or + (positronic)
what does beta ratiation lose during collisions
energy
antineutrino is always produced in whattype of beta radiation decay
B-
neutrino is always produces in what decay of beta radiation
B+
what charge is gamma radiation
no charge
when atom decays and emits gamma radiation what changes and what doesn’t change
structure of nucleus doesn’t change - state of excitation does
larger decay constant the fast the ____ decrease
number of radioactive atoms
explain the half life
time required for amount of radionuclide to decrease to half the starting value
Break radiation is called what
Bremmstrahlung
treating inner-shell electrons as hydrogen like energies is what form of x rays
characteristics xray s
sealed tub containing gass at low pressure with anode and cathode is called what
generation of X-rays
upper atmosphere creates neutrons, some of which reach the lower atmosphere and interact w/ nitrogen to create a radioactive isotop of carbon
- what is this
carbon dating
when a particle and its anti-particles meet
- they annihilate and their mass is converted to enrgy
- 2 photons of equal energy must be created in order to conserve momentum
annihilation
what type of radiation goes the furtherest
gamma
with higher electrons will the radiation go further or shorter
further
with a solution that is more dense will radiation go further or shorter
shorter in more dense solution
attenuation of radiation by matter is what type of process
exponential
what are more ionisation and interact more often
- between alpha and beta radiation
alpha
alpha radiation is particularly dangerous to biological tissue but only if the tissue is in close contact with the ___ _____
alpha emitter
three ways X and gamma radiation interact with matter
- photoelectric effect
- compton scattering
- pair production
ioising radiation causes damage to genetically important molecules occasionally by direct hit but more often ____ by the creation of free radicals
indirect
deterministic effects are
1. early of late
2. lethal or non lethal damage
early
lethal
units of sievert (Sv) is or rem(roentgen equivalent man) measures what
roentgen equivalent man
what does a PET scan use
positron emitting nucide
the activity of a sample is related to what
how many atoms are decaying in a second
what equation would you use for activity of a sample
A= (lamdar) xN
what equation would you use for a decay constant
lamnar = 0.693/t(1/2)
what is nuclear decay
process of an unstable nucleus transform into more stable (may still be unstable)
