Answer the following question regarding the modern version of Mendeleev's periodic table.
Name the total number of groups which are further subdivided into subgroup A and B.
In the modern version of Mendeleev's periodic table, groups are numbered in Roman numerals from I to VIII.
A total of seven groups are sub divided into sub-groups A and B.
Groups: The vertical columns in the Mendeleev's periodic table are known as groups.