Sodium (Na)


  • Symbol: Na
  • Atomic Number: 11
  • Atomic Weight: 22.98976928
  • Element Classification: Alkali Metal
  • Discovered By: Humphry Davy
  • Discovery Date: 1807
  • Name Origin: English: from soda; Medieval Latin: ‘sodanum’, a headache remedy
  • Density(g/cc): 0.971 (at 20°C)
  • Melting Point: 97.79°C
  • Boiling Point: 883°C
  • Appearance: Soft, silvery-white, very reactive metal
  • Atomic Radius(pm): 186


Sodium was first isolated by Humphry Davy in 1807 through the electrolysis of caustic soda (NaOH), shortly after his discovery of potassium. This breakthrough was part of a series of discoveries using electrolysis to isolate elements, showcasing the power of electric current in chemical reactions. Davy’s work led to the recognition of sodium as a distinct element, previously known only in compound forms.

Relation to Other Elements

Sodium is a member of the alkali metals group in the periodic table, characterized by their single electron in the outer shell, which they readily lose to form cations with a +1 charge. Like other alkali metals, sodium is highly reactive, especially with water, releasing hydrogen gas and forming sodium hydroxide. Its reactivity is due to its relatively low ionization energy, which allows the outer electron to be removed easily. Sodium’s chemical properties are similar to other group 1 elements, though it is less reactive than potassium and more so than lithium.

Natural Occurrence

Sodium does not occur in nature in its metallic form due to its high reactivity. It is abundantly found in the Earth’s crust in various minerals, such as halite (NaCl), sodalite, and feldspar. Sodium compounds are also dissolved in ocean water, giving the sea its saltiness. The element plays a critical role in biological systems, serving as an essential electrolyte in the body, involved in nerve function and muscle contraction.


Sodium has a wide range of applications, reflecting its abundance and chemical properties:

  • Chemical Industry: Sodium is used in the production of various chemicals, such as sodium peroxide, sodium amide, and sodium cyanide.
  • Metallurgy: It serves as a powerful reducing agent in the extraction of metals from their ores.
  • Street Lighting and Electronics: Low-pressure sodium lamps are highly efficient and emit a characteristic yellow light, used in street lighting and for astronomical observatory purposes due to their narrow spectral output.
  • Soap and Glass: Sodium hydroxide (lye) is used in the manufacture of soap, while sodium carbonate (soda ash) is a key ingredient in glassmaking.
  • Medicine and Biology: Sodium ions are essential for the physiological functions of the human body, including fluid balance, nerve transmission, and muscle contraction.

Sodium’s discovery and its subsequent applications have had a profound impact on industry, technology, and medicine, illustrating the significance of this highly reactive element in daily life and industrial processes.

Neon (Ne)

Magnesium (Mg)