The metallic lustre exhibited by sodium is explained by:

Explanation

Sodium is an element with symbol Na and atomic number 11. Sodium is a metal. Metallic lustre of sodium is because of the oscillation of loosely bound electrons. When light falls on the surface of the metal, free electrons in the metal get excited to higher energy levels and when it returns back to the lower energy levels, it emits light. Metals have a bright physical appearance. Metals are shiny and lustrous. The colour of solid sodium is silvery-white. The free sodium metal does not occur in an environment prepared or obtained from its compounds. Sodium is an alkali metal which is present in group 1 of the periodic table, as it has one valence electron. The atomic mass of sodium is 23. Sodium metal exists in various minerals such as rock salt, feldspar and sodalite. Sodium ions are soluble ions in aqueous solutions.