Atomic structure Flashcards
what is atomic energy?
it is the attraction between the nucleus and the orbiting electrons
does the chemical properties remain the same for isotopes?
yes
what is a radioisotope?
imbalance between neutrons and protons becomes too large
what is radioactivity?
spontaneous emission of particles, EM radiation or both due to an unstable nuclei
what is nuclear BE?
energy to split a nuclei into its component nucleons
what is a radioactive family?
describes the multiple decay process until a stable nucleus is reached
what is the number of protons called?
atomic number
what are the shells?
k = 2, l = 8, m = 18
what are the shells?
k = 2, l = 8, m = 18
what are leptons?
lightweight particles, which can’t further divide i.e electrons
what are hadrons?
heavyweight particles which can further divide i.e protons and neutrons (quarks)
what is the charge in up quarks?
+2/3
what is the charge in down quarks?
-1/3
what happens when protons repel?
cause the nucleus to break
properties of alpha particles?
- low velocity
- short distance
- influenced by magnetic and electric fields
- large mass
- +2e charge
- interactions likely lose energy
- radium 223 alpha emitter
what is the number of protons and neutrons in alpha?
2 protons and 2 neutrons (2+ charge)
reduces the ration of p: n making it more stable, emission is associated with the breakdown of heavy elements
(226, 88) -> (222, 86) + (4,2 alpha)
describe the BE of the shells?
BE for k is greater due to being closer to the nucleus, attraction is greater, energy decreases as the number of shells increases, in order to remove an electron this energy must be overcome
what are the 2 forms of beta particles?
positive and negative
what is the beta mass = to?
electron mass
what happens when beta particles hit a liquid?
leaves a track of light which bounces everywhere, superficial uses for treatment
what is beta negative?
it is when a neutron becomes a proton, an electron (negatrons) and an antineutrino.
it has the same charge as an electron
why does a beta particle become negative?
when there is excess neutrons
what are the beta emitters?
strontium -89, samarium, which are taken up like calcium in bone, useful for bone metastases
what are beta negative properties?
- causes ionisation in any transverse medium
- deflected by magnetic and electrical fields
- act as electrons
- localised damage to tissues
- greater range
how does a beta positive form?
it is when there is excess protons, so a proton changes to a neutron, a positron (+ electron) and a neutrino
the neutron: proton ratio is too low
what happens to the number of p and n when a beta + forms?
number of neutrons increases by 1 and proton number decreases by 1
what happens to the deflection of beta positive?
they are deflected by electrical and magnetic fields in the opposite direction
what is an antineutrino?
it is the antimatter of a neutrino, which carries no charge at rest, with no mass. When in motion it possesses energy
what is the difference between antineutrino and a neutrino?
intrinsic spinning motion
production of gamma radiation?
it occurs when the nucleus sheds its surplus energy by emitting one or more photons of high energy EM radiation
what is metastable state?
temporary excited condition of the radionuclide
what is isometric transition?
subsequent transition from metastable to stable
what is the gamma ray?
photon/ high energy + short wavelength
what is annihilation energy?
it is when a positron and electron collides destroying each other, creating a photon burst and two gamma rays (each have 0.51 MeV, travel 180 from each other)
properties of gamma rays?
- not influenced by electrical and magnetic fields
- no mass
- no charge
- more penetrating
- ionising
- EM radiation
what are the values for gamma rays?
1.17 MeV and -1.33 MeV
when is gamma radiation used?
deep lying lesions
what is a use of gamma radiation?
Radionuclide imaging and radiotherapy
What is also produced alongside 2 gamma rays?
a more stable nuclei and a negatron
