Sodium

 The chemical symbol Na stands for the element Sodium. 🧂

The symbol comes from its Latin name, Natrium.

Essential Information

 * Symbol: Na

 * Atomic Number: 11

 * Atomic Mass: \approx 22.99 u

 * Classification: Alkali Metal (Group 1, Period 3).

 * State at Standard Temperature and Pressure (STP): Soft, silvery-white solid metal.

Key Properties and Uses

 * High Reactivity: Elemental sodium metal is highly reactive, especially with water, where it reacts vigorously (sometimes explosively) to form sodium hydroxide and flammable hydrogen gas. Because of this, it is never found in its pure form in nature and must be stored under oil or in an inert atmosphere.

 * Biological Importance: The sodium ion (\text{Na}^+) is an essential macronutrient and electrolyte in the human body. It is vital for regulating blood pressure, fluid balance, and the function of nerves and muscles.

 * Common Compounds: Sodium is primarily encountered in its compounds, the most common being:

   * Sodium Chloride (\text{NaCl}): Common table salt, widely used in food seasoning and as a preservative.

   * Sodium Hydroxide (\text{NaOH}): Also known as lye or caustic soda, used in soap and paper manufacturing.

   * Sodium Bicarbonate (\text{NaHCO}_3): Baking soda, used in cooking and antacids.

 * Industrial Uses: Sodium vapor lamps are widely used for street lighting, producing a distinct brilliant yellow-orange light. Pure sodium metal is also sometimes used as a heat transfer agent in nuclear reactors.