When sodium is exposed to air, it undergoes a chemical reaction with oxygen to form sodium oxide. This reaction is an example of oxidation, where sodium loses electrons to oxygen. The sodium atoms lose their shiny metallic appearance and turn black due to the formation of sodium oxide.
The chemical equation for this reaction is:
4Na(s) + O2(g) → 2Na2O(s)
In this reaction, sodium atoms (Na) react with oxygen molecules (O2) to produce sodium oxide (Na2O). Sodium oxide is a black, flaky substance that is insoluble in water.
