Final answer:
Group A is called column 1A and 2A in the US numbering system, and group 1 and 2 in the European system. Group 7A is known as halogens, while group 2A is called alkaline earth metals. ABO blood groups are determined based on antigens A and B.
Step-by-step explanation:
In the traditional numbering system used in the United States, group A is also known as column 1A and 2A, while group B is made up of the middle groups. In the European numbering system, group A is designated as group 1 and 2, while group B is made up of the transition elements.
Furthermore, specific groups on the periodic table have their own names. Group 7A (or 17) is called halogens, while group 2A is known as alkaline earth metals.
Additionally, ABO blood groups are designated by the presence or absence of specific antigens A and B on erythrocyte surfaces.