Question

Study the periodic table and describe its important features.

Answer 1

• The systematic arrangement of elements according to the increasing order of their atomic number is called the periodic table.
• The main features of modern periodic law are as follows:

1. Elements are arranged in the increasing order of their atomic numbers.
2. Horizontal rows in the periodic table are called periods and vertical columns in the table are called groups.
3. Elements in the periodic table are arranged in 7 periods and 18 groups.
4. Elements are so arranged that elements with similar atomic numbers(and hence, similar chemical properties ) appear in vertical columns.