Give the ‘liquid elements’ in the periodic table.

What is valency of an element?

5.

Gallium was named by Mendeleev as

What are magic numbers?

Which property is the basis of long form of periodic table?

How many elements are placed in each period of the p-block?

What is the number of groups in: (i) p-block  (ii) d-block?

How many elements are present in:
(i) second period    
(ii) fourth period    
(iii) sixth period?