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Name: Karen M.
Status: educator
Age: 20s
Location: N/A
Country: N/A
Date: 2001 - 2002

Why is it that when magnesium is tested as a flame test it is colourless not bright white?

For an element to have a characteristic color in a flame test, it must have an exited electronic state that emits radiation in the visible part of the electromagnetic spectrum -- between about 400 and 700 nanometers. Magnesium does not have an excited electronic state corresponding to these wavelengths, so it emits no visible radiation. If it emitted visible light equally across this wavelength range it would appear white. I don't know of any element for which that is the case. Most elements emit a narrow band of visible light.

Vince Calder

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