(a) Elements, A, B, C and D have atomic numbers `12, 19, 29 and 36` respectively. On the basis of electronic configuration, write to which group of the periodic table each element belongs.
(b) Predict the blocks to which these elements can be classified. Also predict their periods and groups.
(c ) Which of these are representative elements ?

Explanation

To solve the question step by step, we will analyze the electronic configurations of the elements A, B, C, and D based on their atomic numbers and classify them accordingly.

### Part (a): Determine the Group of Each Element

1. **Element A (Atomic Number 12)**:
- Electronic Configuration:
- 1s² 2s² 2p⁶ 3s²
- The last electron enters the 3s subshell.
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