The Periodic Table: Group 1

Group 1 elements are known as Alkali metals.
Alkali metals include Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).
These metals are very reactive due to only having one electron in their outer shell and therefore, readily donate this electron to achieve a stable electronic structure.
Reactivity increases down the group. This is because the outer electron gets further from the nucleus, and so is more easily lost to form a positive ion.
All alkali metals have similar properties because they all have one electron in their outer shell. They are soft, have low melting points and they conduct electricity.
Alkali metals react vigorously with water, producing a hydroxide and hydrogen gas. For example: 2K(s) + 2H2O(l) -> 2KOH(aq) + H2(g).
Potassium and Sodium are stored under oil to prevent reaction with oxygen or moisture in the air.
Alkali metals form ionic compounds with non-metals. The metal atoms lose their outer electron to become positive ions.
The ions in an ionic compound are held together by strong electrostatic forces of attraction, known as ionic bonds.
The compounds that alkali metals form with non-metals are all white solids that dissolve in water to form colourless solutions.
When alkali metals react with chlorine, they form salts called halides.