Why does the magnesium ion not have a flame colour?
Jenkin replies Read carefully the the section of the Nuffield Chemistry Students’ Book headed ‘Interpretation of the emission spectra of elements (pages 55 – 56). You will gather from this that when compounds of various metals are heated in a flame they vaporise. Some of the energy they are given is absorbed by the metal ion’s electrons which are ‘promoted’ to higher energy levels. We believe that electrons can only have certain specific energies (you might think of them in the same way as bottles on shelves: the bottles can only have a potential energy corresponding to the height of a particular shelf). When an electron falls back to a lower energy level, a quantity of energy corresponding to the difference between the higher and the lower energy level is given out. There is a mathematical relationship between the quantity of energy and its frequency: Energy = a constant (called Planck’s constant) x frequency If you now look at the ‘Background’ diagram on p 57 of the Nuffield Chemistr
