Y1 Ch 03 Electrons and Energy Levels Flashcards
Electrons gain and lose energy by …
Losing/gaining photons.
To move up an energy level the electron must absorb …
a photon that had the exact same amount of energy as the difference between the two energy levels.
Excitation
when an electron moves up an energy level.
Quickly after excitation the electrons …
fall back due to the unstable nature of the electron.
Ionisation
when an electron gains so much energy that it leaves the atom.
A diffration grating is …
A piece of transparent material ruled with very closely spaced lines, used to see the diffration of light.
Continuous spectrum
A spectrum where all frequenies of radiation or colours of light are possible.
Line spectrum
A spectrum of discrete colours of light.
Emission spectra
A bright spectrum seen when photons are emittied by atoms.
Absorption spectrum
A spectrum of dark lines seen on a coloured background produced when a gas absorbs photons.
Spectra are formed because
When the electrons fall down from their excited state they release a photon with the same amount of energy as the differnce between the two energy levels. This photon will have a certain fequency due to E = hf. So only certain frequenies are shown.
Fluoresence
When a substance absorbs short wavelegth electromagnetic radiation and emitts longer wavelength radiation.
Fluorescent tube
A type of light bulb that gives out light when its inner coating fluoresces.
Thermionic emission
When the free electrons are released from a heated filament.
Plasma
A mixture of ions and electrons on a gas.
