(a) Electromagnetic radiation and atomic spectra

how can electromagnetic radiation be described as

a wave and a particle and has dual nature

what happens when electromagnetic radiation is absorbed or emitted by matter

it behaves like a stream of particles

what are the stream of particles known as

photons

what does a photon carry

quantised energy proportional to the frequency of radiation

what happens when a photon is absorbed or emitted

energy is gained or lost by electrons within the substance

what is the difference between a photon in high frequency radiation to one in low frequency radiation

photons in high frequency radiation can transfer greater amounts of energy

what is the formula for the energy associated with a single photon

E = hf or E = hc/λ

what is the formula for the energy associated with one mole of photons

E = lhf or E = lhc/λ

when energy is transferred to the atoms what happens to the electrons in the atoms

may be promoted to higher energy levels

when does an atom emit a photon of light energy

when an excited electron moves from a higher energy level to a lower energy level

what does the light energy emitted by an atom produce

a spectrum

what is a spectrum made up of

a series of lines at discrete (quantised) energy levels. This provides direct evidence for the existence of these energy levels

what does each element in a sample produce

characteristic absorption and emission spectra

what can the spectra be used for

identifying and quantifying the element

what happens in absorption spectroscopy

electromagnetic radiation is directed at an atomised sample. Radiation is absorbed as electrons are promoted to higher energy levels

how is an absorption spectrum produced

by measuring how the intensity of absorbed light varies with wavelength

in emission spectroscopy, what are high temperatures used for

to excite the electrons within atoms

what happens as electrons drop to lower energy levels

photons are emitted

how is an emission spectrum of a sample is produced

by measuring the intensity of light emitted at different wavelengths

In atomic spectroscopy what is the concentration of an element within a sample is related to

the intensity of light emitted or absorbed

Explain why there is a series of lines at discrete wavelengths in the emission spectrum

Different (electron) transitions, Different energy levels/subshells