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The Periodic Table

What are the Alkali Metals?

The alkali metals are in group 1 on the left of the periodic table.

The alkali metals are lithium, sodium, potassium, rubidium,
caesium and francium. You will study the chemistry of lithium,
sodium and potassium. The next three members, rubidium,
caesium and francium, are all too reactive or unstable to be used.
All you need to know about these three is that they have the
same chemical properties as lithium, sodium and potassium.
The alkali metals are extracted by electrolysis.
For shortcuts to the pages of this section, see the alkali metals.

What are the Properties of the Alkali Metals?

1. The alkali metals are all highly reactive elements,
losing their 1 outer electron to form a 1+ ion with non-metals.
The alkali metals react with oxygen, water and halogens.
See the properties of some of the alkali metal compounds.

The alkali metals have to be stored under oil, or they react
with oxygen in the air. They are the most reactive metals.
Potassium and sodium are at the top of the reactivity series.

2. The alkali metals have the common properties of metals being
silvery-grey in colour and good conductors of heat and electricity.

3. The alkali metals are unusually soft, and can easily be cut
with a knife. They are shiny when freshly cut but quickly go dull
(they tarnish) because they react with oxygen (see above).

4. The first three members, lithium, sodium and potassium,
are the only metals which are less dense than water (they float!).

5. The alkali metals have low melting points and boiling points
(for metals). Potassium melts at 63 °C
(see the melting points of the elements for the others).

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