why group 2 elements called alkaline earth metals
Alkaline earth metal The alkaline earth metals are named after their oxides, the alkaline earths, whose old-fashioned names were beryllia, magnesia, lime, strontia, and baryta. These oxides are basic (alkaline) when combined with water. "Earth" is an old term applied by early chemists to nonmetallic substances that are insoluble in water and resistant to heating—properties shared by these oxides. The realization that these earths were not elements but compounds is attributed to the chemist Antoine Lavoisier. In his Traité Élémentaire de Chimie (Elements of Chemistry) of 1789 he called them salt-forming earth elements. Later, he suggested that the alkaline earths might be metal oxides, but admitted that this was mere conjecture. In 1808, acting on Lavoisier's idea, Humphry Davy became the first to obtain samples of the metals by electrolysis of their molten earths,[24] thus supporting Lavoisier's hypothesis and causing the group to be named the alkaline earth metals.
Properties of metals, metalloids and nonmetals Metals comprise the large majority of the elements, and can be subdivided into several different categories. From left to right in the periodic table, these categories include the highly reactive alkali metals; the less reactive alkaline earth metals, lanthanides and radioactive actinides; the archetypal transition metals, and the physically and chemically weak post-transition metals. Specialized subcategories such as the refractory metals and the noble metals also exist.