Group 1: The Alkali Metals


Group 1 is the first group in the periodic table containing elements that are commonly known as the Alkali metals. They are all metals and increase in reactivity down the group and when reacted with water form alkali solutions

The Alkali metals are the most reactive metals in the periodic table. From Lithium and its sizzling reaction with water all the way to the explosive caesium. Alkali metals have one electron in their outer shell and tend to donate this electron in reactions with non metals to form ionic compounds. Alkali metals increase in reactivity and owe their high reactivity to the large atomic radius the lone electron is far from the nucleus. With relatively low ionisation energies group 1 metals are very reactive. Alkali metals will readily react with water to form hydroxides and react with oxygen during oxidation.

Terms in section
Alkali metals

Alkali metals are located in group 1 of the periodic table. Have a single valence electron which is easily lost from the outer shell. Alkali metals react readily with water to form hydroxides and alkaline pH solutions.


The electron is the smallest sub atomic particle that make up the atom. Has a negative charge and is located in shells that orbit the nucleus

Outer shell

Outer electrons is the term given to the shell/energy level furthest from the nucleus containing the electron furthest from the nucleus

Atomic radius

Atomic radius is the distance measured from the nucleus to the outer valence electrons – measured in pm picometres which is 1x10-12 m


A hydroxide is a compound that contains an oxygen and. hydrogen atom bonded together an ion to form the OH- ion which is known as the hydroxide ion


Oxidation is the term given to the process when an atom loses an electron to become a positively charged ion

Ionic compound

An ionic compound is a bond that forms between metals and non metals to form a large ionic lattice


Common Groups and Periods of the Periodic Table


Group 2: The Alkaline Earth Metals