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| 1. | Chemistry. a soft, silver-white, metallic element that oxidizes rapidly in moist air, occurring in nature only in the combined state, and used in the synthesis of sodium peroxide, sodium cyanide, and tetraethyllead: a necessary element in the body for the maintenance of normal fluid balance and other physiological functions. Symbol: Na; atomic weight: 22.9898; atomic number: 11; specific gravity: 0.97 at 20°C. |
| 2. | Medicine/Medical, Pharmacology. any salt of sodium, as sodium chloride or sodium bicarbonate, present in or added to foods or beverages as a seasoning or preservative and used in many pharmaceutical products as an antacid, anticoagulant, or other agent. |
so·di·um (sō'dē-əm) n. Symbol Na A soft, light, extremely malleable silver-white metallic element that reacts explosively with water, is naturally abundant in combined forms, especially in common salt, and is used in the production of a wide variety of industrially important compounds. Atomic number 11; atomic weight 22.99; melting point 97.8°C; boiling point 892°C; specific gravity 0.971; valence 1. See Table at element. [sod(a) + -ium.] |
sodium so·di·um (sō'dē-əm)
n.
Symbol Na
A soft, light, highly reactive metallic element that is naturally abundant, especially in common salt. Atomic number 11; atomic weight 22.99; melting point 97.7°C; boiling point 883°C; specific gravity 0.971; valence 1.
| sodium (sō'dē-əm) Pronunciation Key
Symbol Na A soft, lightweight, silvery-white metallic element of the alkali group that reacts explosively with water. It is the most abundant alkali metal on Earth, occurring especially in common salt. Sodium is very malleable, and its compounds have many important uses in industry. Atomic number 11; atomic weight 22.99; melting point 97.8°C; boiling point 892°C; specific gravity 0.971; valence 1. See Periodic Table. |