-There are a total of 18 groups in the periodic table.
-There are two different numbering systems that are commonly used to classify groups in the periodic table.
-The traditional system used in the united states involves the use of the letters A and B. The first two groups are 1A and 2A, while the last six groups are 3A till 8A. The middle groups use B in there titles .
-The official system for numbering groups would be a 1 through 18 from left to right simply.
-Many periodic tables show both systems simultaneously.