The Alkaline Earth Metals (Group 2)
The Alkali Earth Metals
The series of elements that form Group 2 of the Periodic Table; beryllium, magnesium, calcium, strontium, barium and radium (which is not always considered a membe due to its radioactivity).
The alkaline earth metals are named after their oxides, the alkaline earths, whose old-fashioned names were beryllia (BeO), magnesia (MgO), lime (CaO), strontia (SrO) and baryta (Ba(OH)2). These were named alkaline earths because of their intermediate nature between the alkalis (oxides of the alkali metals) and the rare earths (oxides of rare earth metals).
Properties and Reactions
The alkaline earth metals are silvery coloured, soft, low-density 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. For example, where sodium and potassium react with water at room temperature, magnesium reacts only with steam and calcium with hot water.
Beryllium is an exception: It does not react with water or steam, and its halides are covalent.
All the alkaline earth metals have two electrons in their outermost shell, so the energetically preferred state of achieving a filled electron shell is to lose two electrons to form doubly charged positive ions.