What Is Sodium?
Sodium, an alkali metal with the atomic number 11 and symbol Na, is known for its high reactivity. Its atomic weight is 22.99. Sodium is commonly found in nature in the form of sodium chloride (table salt), carbonates, and nitrates, and is produced industrially through the electrolysis of molten salts.
Applications of Sodium
Due to its reactivity, sodium serves as a reducing agent or catalyst in metal refining processes. Its low melting point and good thermal conductivity make it suitable as a coolant in fast-breeder nuclear reactors. Sodium lamps, utilized in highway and tunnel lighting, along with its use in soap, highlight its presence in daily life. Additionally, it plays a crucial role in maintaining normal muscle and nerve function in the human body.
Physical and Chemical Properties
Sodium is a soft, silvery-white metal with a melting point of 98°C and a boiling point of 883°C. It is lighter than water, with a specific gravity of 0.97. Sodium reacts explosively with water, acids, and bases, and oxidizes in air, requiring storage in kerosene to prevent reaction.
Molecular Structure and Isotopes
At room temperature, sodium adopts a body-centered cubic structure with an electron configuration of [Ne] 3s1. It transforms under high pressure, becoming transparent. Sodium has 20 known isotopes, but only 23Na is stable, with 22Na and 24Na occasionally detected in rainwater.
Industrial Production
1. Electrolysis Methods
Sodium is primarily produced via electrolysis of molten salt, using either the Castner or Downs’ process. The Castner process electrolyzes sodium hydroxide, while the Downs process uses sodium chloride, potentially with calcium chloride or potassium chloride to lower the melting point.
2. Chemical Reactions
Sodium’s interaction with water forms hydrogen gas and sodium hydroxide. It can also form sodium hydride when heated with hydrogen and reacts with alcohols, phenols, and carboxylic acids to produce alkoxides. Sodium’s reduction properties facilitate the extraction of metals like titanium, thorium, tantalum, and zirconium.