Question

Solve this:
Q. (d) State the modern periodic law. How many groups and periods are present in modern periodic table ?

Answer 1

Mendeleev's periodic law:The properties of element are the periodic function of their atomic masses

The modern periodic table has 18 vertical columns known as groups. i.e 18 Groups in modern periodic table

the modern periodic table has 7 horizontal rows known as periods i.e 7 periods in modern periodic table