Understanding Flame Tests and
Emission Spectra
Electron Cloud Arrangement
The electron cloud is arranged
into various regions called
energy levels.
The energy level closest to the
nucleus is the lowest energy
level and numbered “1”.
Each energy level after
increases in number and
requires more energy to be
occupied.
Electron movement
Electrons moving in the
electron cloud require a
certain amount of energy.
This energy allows them to
move around the nucleus.
Remember that there
aren’t really fixed orbits, but
the image helps give you an
idea of what we’re talking
about.
Electron Excitation
When electrons have their “usual” amount of energy this is called
the ground state. These electrons travel around the lowest possible
energy level.
However, if an outside source (like electricity or fire) provides
energy to these electrons they will gain energy and “jump” to a
higher energy level. This is known as the excited state.
Fall back
After a short amount of
time, the electron will lose
this extra energy, and return
to the original lower energy
level.
In the process the extra
energy is released as a
photon (light)
Photons = light
The amount of energy
released by the excited
electron can be
interpreted by our eyes
as various colors.
Light
Visible light is only a small portion of the electromagnetic spectrum.
Our eyes can only interpret a small range of these waves.
Imagine what X rays would look like? Or Microwaves?
Color and Energy
Each color we can see, is actually a different wavelength of energy.
Reds have very large wavelengths, and carry less energy than Blues
and Purples, which have shorter wavelengths and pack more
energy.
Spectroscopy and the elements
• The experiment conducted takes advantage of prisms, and
their ability to break light up into the individual colors
(wavelengths) that are present.
Each element produces a
unique patterns of light, due
to the photons released by the
excited atoms falling back to
their ground state.
Therefore, the banding
patterns can be used to ID
elements.
Flame Test
Similar to the emission
spectrum, elements,
when burned also give
off light.
Elements give off
signature colors, and can
be used to help ID
elements
Objective
Identify the unknown element using the
spectroscopes. It is one of the other 5 you are
observing!
Identify the unknown elements using the flame test.