Excitation and photons

What’s meant by excitation

When electrons move up energy levels

What would happen if an electron with energy lower than the ground state was about to collide with the atom

It would repel

What would happen if the electron colliding with the atom had a potential energy I between two energy shell levels

The electron would get excited and make it to the highest possible energy level and the extra kinetic energy would remain with the colliding electron as ionisation didn’t take place

How do we work out the kinetic energy of a free electron after excitation

Ek = energy of incoming electron - excitation energy

The excitation energy is known because u can’t subtract an energy levels potential difference and it be bigger than the energy of the incoming electron because then it would move higher

What happens when an electron de-excites

It releases energy in the form of a photon

The greater the energy difference between the energy levels

The more energetic the photon released

What do we do with the energy of electrons in de excitation questions

Convert from J to eV

What else can excite an atom and what are the conditions for this

A photon

An electron will only absorb energy from a photon if it has the exact amount of excitation energy

What can photons do other than exciting an atom

Ionising an atom

In ionisation the extra energy gets converted into the kinetic energy of the electron just like with ionisation with an electron