Question

The atomic number of an element $M$ is $26$. How many electrons are present in the M-shell of the element in its $M^{3+}$ state

• A. 11
• B. 15
• C. 14
• D. 13

Answer 1

Answer: (D)

13

Answer 2

$M(Z = 26): 1s^2 2s^1 2p^6 3s^2 3p^6 4s^2 3d^6$ $M^{3+} : 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5$ Mth shell means $n = 3$ i.e., $3$rd shell. In $M^{3+}$, $3$rd shell has $13$ electrons.