Question

How many electrons are present in the M-shell of an atom of the element with atomic number $Z=24$?

• A. $5$
• B. $6$
• C. $12$
• D. $13$

Answer 1

The correct option is D $13$

Atomic no:-24
E.C is: $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^5$ [Extra stability of half filled orbitals]

M shell means 3rd shell $3s^{2}3p^{6}3d^5$
$Mshell\to 13$