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The Periodic Table

The Alkali Metals - Group 1Reaction with Water.

How do the Alkali Metals React with Water?

The alkali metals lithium, sodium and potassium all react with
cold water forming a soluble alkaline hydroxide and hydrogen gas.
You must know how to test for hydrogen gas!
All three metals are less dense than water and so they float.

How does Sodium React with Water?

Sodium melts and forms a floating ball of metal which fizzes
as it moves over the surface of the water giving off hydrogen gas.

sodium  +  water   arrow  sodium hydroxide   +   hydrogen.
2Na(s)  + 2H2O(l)  arrow         2NaOH(aq)       +        H2(g)  

How does Lithium React with Water?

Lithium is less reactive than sodium and does not melt but
does react quickly with cold water giving off hydrogen gas.

lithium   +   water   arrow  lithium hydroxide   +   hydrogen.
2Li(s)  +  2H2O(l)  arrow           2LiOH(aq)       +       H2(g)  

How does Potassium React with Water?

Potassium is the most reactive. It melts, reacts vigorously and burns
with a lilac flame as it gives off hydrogen gas. Potassium is
dangerous and can explode when it comes into contact with water.

potassium + water  arrow   potassium hydroxide + hydrogen.
2K(s)  +  2H2O(l)   arrow          2KOH(aq)           +    H2(g)   


All the hydroxides are strongly alkaline. Note the state symbol
(aq) after the hydroxide, showing that it is dissolved in water.

The alkali metals are so named because they form
alkaline hydroxides in water. The metals
themselves are not alkalis, they are just metals (neutral).

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