List of practice Questions

Consider the following species: N^3- , O^2-, F^-, Na⁺, Mg²⁺ and Al³⁺ 

1. What is common in them? 
2. Arrange them in the order of increasing ionic radii.

In the modern periodic table, the period indicates the value of:

Which of the following statements related to the modern periodic table is incorrect?

What is the basic difference in approach between the Mendeleev's Periodic Law and the Modern Periodic Law?