A Visual Encyclopedia of the Periodic Table

26

Alkali Metals

Forms

Sodium

Na

11

This sodium-rich

mineral is an example

of a zeolite, a mineral

with tiny holes that

can trap gases.

Everyday salt contains lots of sodium.

Although abundant on Earth, sodium is

never found in its pure form naturally: it forms

compounds with other elements. Sodium chloride,

which also contains chlorine, is the most common

sodium compound. It is also known as the mineral

halite, and it is what makes seawater salty. Other

sodium minerals include sodalite, a soft blue

stone that can be shaped and polished. Pure

sodium is soft enough to be cut with a knife.

It reacts with oxygen in the air, forming a

compound called sodium oxide, and bursts

Laboratory sample of

pure sodium in an airless vial

This glass case

holding pure sodium has

no air in it, to prevent

the metal from reacting

with oxygen in air.

Polished gemstone made

of the mineral sodalite

Cube-shaped

transparent cr ystals Salar de Uyuni, Bolivia

The thick, white crust

covering this salt flat contains

sodium chloride and other salts.

11 11 12

State: Solid

Discovery: 1807

Soft, shiny metal

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