Which of the following correctly represent the electronic distribution in the Mg atom?
3, 8, 1
2, 8, 2
1, 8, 3
8, 2, 2

Correct Answer: (b) 2, 8, 2

Explanation: Atomic number of Mg is 12.

So, according to Bohr's formula of distribution of electrons (2n²), the K shell (n=1) can accommodate 2 electrons, the L shell (n=2) can accommodate 8 electrons and the remaining 2 electrons were accommodated in the M shell. Hence, its electronic configuration is 2,8,2.