Question

What are the main features of Mendeleev’s periodic table?

Answer 1

Main features of Mendeleev’s periodic table :
(i) The horizontal rows in the periodic table are called periods. There are seven periods. These are numbered from 1 to 7.
(ii) Properties of elements in a particular period show regular gradation from left to right.
(iii) Vertical columns in the periodic table are called groups. There are eight groups numbered from I to VIII. Groups I to VII are further divided into A and B  subgroups.