Sodium, symbolized as Na, is a soft, silvery-white metal that belongs to the alkali metal group (Group 1A) on the periodic table. With an atomic number of 11, sodium is a highly reactive element that is not found freely in nature due to its tendency to react with water and air. Instead, it commonly exists in compound form — most notably as sodium chloride (NaCl), or common table salt.
Chemical Properties of Sodium
- Symbol: Na
- Atomic Number: 11
- Atomic Mass: Approximately 22.99 u
- Group: Alkali metals (Group 1A)
- Density: 0.97 g/cm³
- Melting Point: 97.79 °C
- Boiling Point: 883 °C
- Electron Configuration: 1s² 2s² 2p⁶ 3s¹
Sodium is extremely reactive, especially with water, where it produces hydrogen gas and heat, which may cause explosions. Due to this reactivity, it is stored under oil or in an inert atmosphere.
Occurrence in Nature and Extraction
Sodium does not occur in its elemental form naturally. Instead, it is widely found in compounds such as:
- Sodium chloride (NaCl) – Found in seawater and rock salt
- Sodium carbonate (Na₂CO₃) – Known as soda ash
- Sodium sulfate (Na₂SO₄) – Found in salt lakes and mineral deposits
To obtain metallic sodium, industries use electrolysis of molten sodium chloride, a process that separates sodium from its compound.
Role of Sodium in the Human Body
Sodium plays a vital role in human health, but only in its ionic form (Na⁺). Key functions include:
- Water Balance and Hydration: Sodium helps regulate intracellular and extracellular fluid levels.
- Nerve Transmission: It is essential for electrical signal transmission between nerve cells, facilitated by the sodium-potassium pump.
- Muscle Contraction: Sodium contributes to proper function of skeletal and cardiac muscles.
However, excessive sodium intake is linked to high blood pressure, heart disease, and kidney issues. The World Health Organization (WHO) recommends no more than 2,000 mg of sodium per day (about 5 grams of salt).
Industrial Uses of Sodium
Sodium and its compounds are used in a wide range of industries:
- Chemical Industry: Used in organic synthesis and sodium-based compounds production.
- Metallurgy: Used to reduce metals like titanium and zirconium.
- Lighting: Employed in sodium vapor lamps, commonly used in streetlights.
- Nuclear Reactors: Liquid sodium is used as a coolant in some fast-breeder reactors.
- Cleaning Products: Key component in the production of sodium hydroxide (caustic soda) for soaps and detergents.
Conclusion
Sodium is a crucial element both biologically and industrially. While commonly encountered as table salt in daily life, it also plays significant roles in technology, energy, health, and chemical processes. Maintaining balanced sodium intake is essential for good health, as both deficiency and excess can disrupt physiological functions.
