The alkaline earth metals are a group of metals on the periodic table. They are related to the Alkali metals, but they do not react as much because they need more energy to remove their two electrons. So they do not have to be stored in petrol. As ions they have a charge of +2. The alkaline earth metals are silver coloured, soft metals, which react readily with halogens to form ionic salts, and with water, though not as rapidly as the alkali metals, to form strongly alkaline (basic) hydroxides.