1
Q
What is the Bohr model of the atom?
A
- Electrons have fixed energy levels
- Electrons move levels through absorption or losing exact energy
- Energy is lost by emitting a photon of EMRadiation
- Photon’s energy level is equal to difference in energy level: hf = e1 - e2.
2
Q
What is the Bohr electron model?
A
- N1 is closest to nucleus and has least power.
- N3 is two higher, infinity is beyond atom.
- Levels relate to orbits
- eV are electron volts
- 1 eV = 1,602 x 10-19 Joules
3
Q
What is excitation?
A
- when electrons gain energy and move level
- EMRadiation photon is emitted and electron drops level after a short random amount of time
4
Q
What is ionisation?
A
- When electrons gain enough energy to raise to n=infinity
- atom loses an electron
5
Q
What is photo absorption?
A
- When an electron gains energy by absorbing a photon, which then ceases.
- The energy absorbed = the energy between levels.
6
Q
What is an electron collision?
A
A free electron collides with an atomic electron which can transfer kinetic energy.
7
Q
What is elastic scattering?
A
- incident electron doesn’t have enough energy for the atomic electron to change levels.
- bounces off electron, transferring no energy.
- elastically scattered means losing no KE
- KE is conserved
8
Q
What is inelastic scattering?
A
- incident electron has great energy than difference between energy levels.
- transfers some energy to atomic electron, raising it to a higher level
- atomic electron now in excited state
- inelastically scattered: losing energy equal to the difference between energy levels.
- KE not conserved.
9
Q
What is ionisation?
A
- energy level of incident electron greater than requirement to remove atomic electron from orbit.
- atomic electron knocked out of orbit
- excess energy shared between KE of both electrons
10
Q
What is the collision problem formula?
A
Edifference = Efinal - Einitial
- > convert eV to Joules: 1.602 x 10-19
- > Rearrange E = hf
- > F = Energy x Planck’s constant
- > F = energy x 6.63 x 10-34
11
Q
How do you solve indicies?
A
- multiply you add them
- divide them you take away
Nuclear and Atomic Physics
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