Describe the principle and procedure of the flame test.

The principle of the flame test is based on the fact that when certain metal ions are heated in a flame, their electrons absorb energy and get excited to higher energy levels. As these excited electrons return to their ground states, they emit light of specific wavelengths, resulting in a characteristic color for each metal.

• Clean a platinum wire by dipping it in concentrated hydrochloric acid (HCl) and heating it in a non-luminous flame until no color is observed.
• Dip the clean wire into concentrated HCl again.
• Touch the wet wire to a small amount of the solid sample to pick up some of the substance.
• Introduce the wire with the sample into the hottest part of a non-luminous Bunsen flame.
• Observe and record the color of the flame produced.