The Flame Test is a qualitative
analytical procedure used to detect the presence of certain elements
by the color it burns under a flame. The test usually introduces a sample of a compound or element
into a flame. The flame should then change color depending on the specific elements present. For example, the element Arsenic when put into a flame, should give out a blue color, while the element Radium should give out a red color.
The colors associated with the different elements are dependent on two factors: the temperature
of the flame, and each element’s characteristic emission spectrum. For the temperature factor, blue flames burn at a higher temperature than red or yellow flames.
For the emission spectra, each element has its own one. Putting a certain element into a flame will excite its electrons to higher energy levels. Eventually, these electrons will drop back down into the ground state, releasing the energy gained from the flame. This released energy corresponds to a specific wavelength, and by extension a specific color. And so, due to the unique nature of an element’s emission spectra, the element can be identified from the color of the flame in the Flame Test.
The Flame Test is a very fast and easy experiment to perform, which does not require any complex equipment. However, it can be subjective as it depends on the experimenter’s perception of color.