Question

write the principal of modern periodic table​

Answer 1

Explanation:

The present form of a periodic table that is widely used across the globe is the long form of the periodic table. In this form of a periodic table, the horizontal rows are called periods and the vertical columns are known as the groups. ... In the modern periodic table, periods are the seven horizontal rows.

Answer 2

Answer: The present form of a periodic table that is widely used across the globe is the long form of the periodic table. In this form of a periodic table, the horizontal rows are called periods and the vertical columns are known as the groups. ... In the modern periodic table, periods are the seven horizontal rows.