s-BLOCK ELEMENTS

Flame Test : 1. Alkali metal : The alkali metals and their salts impart characteristics colour to an oxidizing flame. This is because the heat from the flame excites the outermost orbital electron to a higher energy level. When the excited electron comes back to the ground state, there is emission of radiation in visible region. Alkali metals can therefore, be detected by the respective flame tests and can be determined by flame photometry or atomic absorption spectroscopy. These elements when irradiated with light, the light energy absorbed may be sufficient to make an atom lose electron. Metal ( colour of flame ) : Li ( crimson red ) , Na ( yellow ) , K ( violet / lilac ) , Rb ( red violet ) , Cs ( blue ). Next topic : FLAME TEST for alkaline earth metals. To be continued ..........