Question

In group 1 of the Periodic Table, three elements X, Y and Z have ionic radii 1.33Å, 0.95Å and 0.60Å respectively. Giving a reason, arrange them in the order of increasing atomic numbers in the group.

Answer 1

 X – 1.33 Å; Y – 0.95 Å; Z – 0.60 Å. 

The order of increasing atomic numbers is : Z < Y < X. This order is due to the fact, that greater is the ionic radii, greater is the atomic number of the element. As the ionic radii increases, the number of electrons increases, i.e., the atomic number increases.