Question

The atomic number of an element is $11$. Therefore the number of electrons in the M-shell of its atom is:

• A. $2$
• B. $8$
• C. $1$
• D. $0$

Answer 1

Answer: (C)

$1$

$M$ shell of an atom means 3rd shell (K, L, M).

The electronic configuration of an atom having atomic number $11$ is $2,8,1$ which shows that the third shell contains $1$ electron.

Hence, option C is correct.