The elements of the periodic table in groups 1A to 8A are called the main-group elements. They are sometimes also called the representative elements and they are the most abundant in the universe.
Some of the main group elements have common names, such as the alkali metals (1A), the alkaline earths (2A), the halogens (7A) and the noble gases (8A). There also is a B group of transition metals that falls in between the 2A and 3A main groups. With the exception of hydrogen, the lanthanides and the actinides, all other elements are main-group elements. The lightest main-group elements are helium, lithium, beryllium, boron, carbon, nitrogen, oxygen and fluorine.
