Question

The alkali metals and their salts impart characteristic colour to an oxidising flame. 

1. What is the reason for this? 

2. Give the flame colour of Na and K. 

3. Name the alkali metal which imparts crimson red colour to the oxidizing flame.

Answer 1

1. When the heat energy is supplied to alkali metal or its salt, the electrons are excited to higher energy levels. When these excited electrons come back to their original energy levels, they emit radiations which fall in the visible region of the electromagnetic spectrum and they appear coloured.

2. Na-Yellow, K-Violet 

3. Li