Wörterbuch (en): Alkaline earth metals (pl)
The elements beryllium, magnesium, calcium, strontium, barium and radium belong to the 2nd main group, the alkaline earth metals. They are all light metals. The reactivity of the alkaline earth metals increases significantly with increasing atomic number. The light metals are divalent and exist (except Be) as double positive cations in compounds. Magnesium and calcium are among the 10 most common elements of the earth's crust.