10.11 Beryllium and magnesium do not give colour to flame whereas other alkaline earth metals do so. Why ?
When the alkaline earth metals are heated the electrons are excited to higher energy levels and when they drop back to the ground state, energy is emitted in the form of visible light. Hence the colour is observed. The electrons in beryllium and magnesium are too strongly bound to get excited by flame. Hence, these elements do not impart any colour.