Atomic Structure and Electron Interactions Flashcards
describe the structure of an atom.
consists of three shells;
K shell - inner
M shell - middle
N shell - outer
what is the electron volt?
the energy (J) required to raise an electron through the potential difference of 1 volt.
What is binding energy?
the amount of energy required to hold the electron in it’s shell, or remove it.
Describe the process of binding energy.
the larger the atom the larger the positive charge of the nucleus which means that the inner K shell electron will be more tightly bound therefore meaning more energy is required to remove electrons from the atom.
Why is less energy required to remove electrons from the outer shell?
this is because the electrons are less tightly bound to the nucleus.
Describe elastic interactions
this is when kinetic energy is conserved while the electron interacts with orbiting electrons, or nucleus of target atom -> which deflects from it’s original path without losing energy.
Describe inelastic interactions
this is when some or all energy is given up to target material.
kinetic energy is lost form incoming electrons therefore excitation and/or ionisation of the target atoms occurs which creates X-ray photons
Define elastic scattering.
the closer the electron travels towards the nucleus, the greater the amount of energy deflections.
What is excitation?
this is when the incoming electron absorbs energy from orbiting electron which then promotes the electron to a “higher” shell.
as time passes the “promoted” electron returns to original orbit and the excess energy is given up as heat to target material.
Define ionisation
the process by which an atom becomes positively or negatively charged. This happen because it gains or loses electron, it can only do this via transfer of energy
Describe step 1 of ionisation
the incoming electron gets energy from orbiting electron which then overcomes the binding energy and leaves it’s own shell and atom to which it belongs.
the electron is now an ion
the ejected electron (delta ray) is capable of producing further excitations/ionisations along it’s own path.
Describe step 2 of ionisation.
There is now a vacancy in the shell where the electron was. An electron from a shell further from the nucleus moves to fill the vacancy.
This electron now has more energy than it needs to exist in this lower energy level, and it gives off the excess in the form of a photon of characteristic radiation.
