Sodium chloride is a compound formed from the ionic bonding of sodium and chloride. Sodium chloride is formed when sodium atoms interact with chlorine atoms. Sodium will donate an electron (which is a negatively-charged particle) to chlorine. This makes sodium slightly positive and chlorine slightly negative. Sodium becomes Na+ and Chlorine becomes Cl- Thus sodium is reduced in this process as it donates the electron and chlorine gain electron and is oxidized.