Nice links enahs, Thanks
Something I have never understood ...
The transition of electrons between energy levels is due to absorption or emission of em quanta of specific energy and hence specific frequency. Say that frequency corresponds to light in the visible spectrum, then why do we see absorption or emission spectra? If the change to a higher level can only come from absorbing a quanta of a very specific energy and colour, then that can only come from light itself. What I'm trying to get at, if we have a flame test of a group 1 or group 2 metal then where is the energy coming from to cause the excitation of the electrons? The obvious answer is the heat in the flame. But won't this heat be of the wrong energy, since only visible light will cause the electron to "jump" to a higher level? To cause an electron transition we would have light in, light out, we wouldn't see anything.
What am I not understanding?
Thanks
Clive