An element ‘X’ belongs to the second group of periodic table. What is the formula of its chloride?

5

Which has smaller size; Na or Na⁺?

6

Which has bigger size; Cl or Cl^-?

8

An element ‘B’ belongs to the second period and Group 13. Give the formula of its oxide.

9

Give two examples of elements of Groups 1, 2, 16 and 17.