1.1 EM radiation and atomic spectra Flashcards
how can electromagnetic radiation be explained
in terms of waves and characterised in terms of wavelength and or frequency
what is the relationship between wavelength, frequency and electromagnetic radiation
c = f lamda
what is the electromagnetic spectrum
this is how the different types of radiation are arranged in order of wavelength
what are wavelengths of visible light normally expressed as
nanometres (nm)
why is electromagnetic radiation described as having a dual nature
it is a wave and a particle
why is electromagnetic radiation described as a particle
when it is absorbed or emitted by matter, it behaves like a stream of particles
what type of particles are electromagnetic radiation
photons
what are photons
these 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
can the photons in high frequency radiation transfer greater or lesser amounts of energy than photons in low frequency radiation
greater
what happens when energy is transferred to atoms
electrons within 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 that is made up of a series of lines at discrete (quantised) energy levels
what is absorption spectroscopy
this is when electromagnetic radiation is directed at an atomised sample
what is absorbed as electrons are promoted to higher energy levels
radiation
how is an absorption spectrum produced
by measuring how the intensity of absorbed light varies with wavelength
what are emitted as electrons drop to lower energy levels
photons
what are used to excite the electrons within atoms in emission spectroscopy
high temperatures
what is an emission spectrum of a sample produced by
by measuring the intensity of light emitted at different wavelengths
what is the concentration of an element related to in atomic spectroscopy
the intensity of light emitted or absorbed
the energy associated with a photon of EM radiation is …
proportional to the frequency
In absorption spectroscopy, as the
concentration of an ion in solution increases,
there is an increase in the
intensity of radiation absorbed
In an emission spectrum of mercury, the line at 310 nm is due to
energy from the ultraviolet region of the electromagnetic spectrum being released
list the electromagnetic spectrum in order of increasing wavelength
gamma
x ray
uv
visible
ir
microwave
radio wave
