MIZORAM Class 10 Chemistry Periodic Classification of Elements
Classification - Early Attempts
Elements are classified on the basis of similarities of their properties.
Dobereiner grouped the elements into triads and Newland stated the Law of Octave.
Mendeleev arranged the elements in increasing order of atomic masses and similarity of chemical properties.
Mendeleev's periodic law states that properties of elements are periodic functions of their atomic massesModern Periodic Table of Elements
Elements in Modern Periodic Table are arranged in order of increasing atomic number
There are 18 vertical columns called groups and 7 horizontal rows called periods.
Atomic size decreases across a period and increases along a group.
Metallic character increases down the group and decreases along a period and vice versa for non-metallic character.