Question

Which of the following correctly represents the electronic distribution in Mg atom?

• A. $3,8,1$
• B. $2,8,2$
• C. $1,8,3$
• D. $8,2,2$

Answer 1

Answer: (B)

$2,8,2$

Atomic number of Mg is $12$. So, according to Bohr's formula of distribution of electrons ($2n^2$), K shell $(n=1)$ can accommodate $2$ electrons, L shell $(n=2)$ can accommodate 8 electrons and the rest 2 electrons are accommodated in M shell. So its electronic configuration is $2,8,2$.

Hence option (B) is correct.