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The Periodic Table

The Alkali Metals - Reaction with Oxygen (burning in air).

How do the Alkali Metals React with Oxygen?

Alkali metals react quickly with oxygen and are stored under oil
to prevent oxygen from reaching the surface of the bare metal.

Lithium, sodium and potassium will all burn in air when
heated to give the corresponding alkaline oxides (see below).
All of the alkaline oxides formed are white powders
which dissolve in water to form strongly alkaline hydroxides.

How does Sodium React with Oxygen?

Sodium burns in air with an orange flame to form sodium oxide.

sodium + oxygen  arrow   sodium oxide.
4Na(s)  +    O2(g)   arrow           2Na

How does Lithium React with Oxygen?

Lithium burns in air with a red flame to form lithium oxide.

lithium + oxygen  arrow   lithium oxide.
4Li(s)  +    O2(g)   arrow       2Li2O(s)

How does Potassium React with Oxygen?

Potassium burns in air with a lilac flame to form potassium oxide.

potassium + oxygen  arrow   potassium oxide.
4K(s)  +    O2(g)   arrow       2K2O(s)

See the flame tests for the different colours of metals.

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