Question

Write the answer to the questions with reference to the periodic table.

1. What do (A), (B), (C), and (D) represent?            [1]
2. Elements are arranged in increasing order of their ______.            [1]
3. Write the electronic configuration of the first four elements in Group I.            [1]
4. What change in atomic radius is observed in moving from left to right in a Period?            [1]
5. Give a reason for (d).            [1]

Answer 1

1. 
   
   (A) represents s-block elements.
   (B) represents p-block elements.
   (C) represents transition elements (d-block).
   (D) represents inner transition elements, i.e., (f-block).
2. Elements are arranged in increasing order of their atomic numbers.
3. The electronic configuration for elements is as follows:
   

   Elements	Electronic configuration
   H	1
   Li	2, 1
   Na	2, 8, 1
   K	2, 8, 8, 1

4. Atomic radius goes on decreasing while going from left to right within a period.

5. The positive charge on the nucleus grows by one unit at a time as the atomic number rises sequentially while moving from left to right over time. However, the same outermost shell receives the additional electron as well. The electrons are more firmly drawn into the nucleus due to the higher nuclear charge, which reduces the size of the atom.