Question

Atomic number of sodium is 11, it has following electronic configuration:

• A. 2(K), 7(L), 2(M)
• B. 2(K), 8(L), 1(M)
• C. 2(K), 2(L), 7(M)
• D. 2(K), 8(L), 2(M)

Answer 1

Answer: (B)

2(K), 8(L), 1(M)

Atomic number of sodium is 11, it has following electronic configuration: $2\left(K\right),8\left(L\right),1\left(M\right)$. Sodium atom donates one electron in its valence shell M, which results in disappearance of M shell and its L shell with eight electrons becomes new valence shell. Thus, it attains the stable electronic configuration of nearest noble gas neon.