All practice pages/Interatomic theory/Elements
Element 11, an alkali metal
A metal soft enough to cut with a butter knife that fizzes and flares on water, and one of the two elements in table salt.
Period 3, group 1. The other alkali metals are tinted, and every cell opens its own article.
One valence electron, which sodium gives up easily to form the Na⁺ ion. Like the other alkali metals, it reacts with water.
The sixth most abundant element in the crust, about 2.4% by mass, always combined: in beds of rock salt, in feldspar minerals, and dissolved in the ocean, where sodium chloride makes up most of the salt. Every cell in your body depends on Na⁺ ions to carry nerve signals.
Humphry Davy isolated it in 1807 by passing electricity through molten sodium hydroxide, days after doing the same for potassium. The name comes from soda. The symbol Na comes from its Latin name natrium, after natron, a natural soda the ancient Egyptians used in mummification.
Sodium chloride seasons and preserves food, melts ice on roads, and is the starting point for making chlorine and sodium hydroxide. Sodium bicarbonate is baking soda. The metal itself lights orange-yellow street lamps, cools some nuclear reactors as a liquid, and helps extract titanium from its ore.
The metal reacts violently with water, releasing hydrogen that can ignite, so it is stored under oil. Sodium hydroxide is strongly corrosive to skin and eyes.