<P> In older nomenclature the main - group elements are groups IA and IIA, and groups IIIB to 0 (CAS groups IIIA to VIIIA). Group 12 is labelled as group IIB in both systems . Group 3 is labelled as group IIIA in the older nomenclature (CAS group IIIB). </P> <P> Main - group elements (with some of the lighter transition metals) are the most abundant elements on Earth, in the Solar System, and in the Universe . They are sometimes also called the representative elements . </P>

With which set of main-group elements does hydrogen share similar properties