Send the link below via email or IMCopy
Present to your audienceStart remote presentation
- Invited audience members will follow you as you navigate and present
- People invited to a presentation do not need a Prezi account
- This link expires 10 minutes after you close the presentation
- A maximum of 30 users can follow your presentation
- Learn more about this feature in our knowledge base article
The Emission Spectrum
Transcript of The Emission Spectrum
What is the Emission Spectrum?
Theory of the Emission Spectrum:
an atom gets excited, by heating and starts to absorb energy.
NaCl gives the flame a colour of orange
BaCl gives the flame a colour of green
KCl gives the flame a colour of red/orangy purple
LiCl gives the flame a colour of red
CaCl gives the flame a colour of red
Then an excited electron in the atom moves to a higher orbit, further away from the nucleus (higher energy level).
When the electron calms down a little bit, it wants to go to where it normally is (it's stabe state).
To do this the electron must get rid of some energy, so it releases a photon (light energy).
When the electron releases the photon, the photon will be of a specific frequency (of a specific colour).
Weirdly, each of the elements in the periodic table will emit different colours when they are excited.
This is what we call the emission spectrum of the element.
In the late 1800’s scientists found that they were able to make atoms emit light. They would do this by heating substances or applying voltages to gases.
The emitted light would then be forced into a glass prism resulting in the light being divided up into its different component colours (frequencies)…
The colours in the spectrum produced by atoms in this way have become known as spectral lines because of the sharp lines they produce on the photographic plate in a spectrometer.
The fact that the spectrum of an element is its ‘fingerprint’ makes it possible to detect tiny traces of elements in complex mixtures, and for astronomers to use the light emitted by remote stars to identify elements in the stars.
If a chemist wants to know what metals are present in a sample, qualitative analysis of an elements emmission spectrum by flame testing can be used.
In a flame test, atoms are excited by the heat of a bunsen burner. As the atoms calm down, they give off radiation, some of it in specifically coloured light.
How can chemists use the emission spectrum?
But how do the atoms do this?
Go do the Prac!