Group 2 (IIA) consists of beryllium, magnesium, calcium, strontium, barium, and radium. This family of elements is known as the alkaline earth metals, or just the alkaline earths. Like those of the Group 1 metals, the oxides of the alkaline earths can be dissolved in water to form bases. Calcium oxide dissolves to form calcium hydroxide, magnesium oxide dissolves to form magnesium hydroxide, and so on.

Early chemists gave the name "earths" to a group of naturally occurring substances that were unaffected by heat and insoluble in water. The more soluble of the earths were called "alkaline earths," a group of substances which we now know as the oxides of the elements of Group 2.

The compounds of Group 2 are usually found in the earth, in contrast to Group 1 compounds which concentrate in the ocean.Calcium carbonate is familiar as limestone, marble, coral, pearls, and chalk--all derived...