Question

Which one of the following does not contains electrons in $4s$ subshells?
Given that : Atomic numbers: $Ti=22,V=23,Cr=24,Mn=25$

• A. $T{i}^{+}$
• B. $V^{+}$
• C. $C{r}^{+}$
• D. $M{n}^{+}$

Answer 1

Answer: (C)

$C{r}^{+}$

Electroni configuration of ${Ti}^{+1}=\left[Ar\right]3d^{2}4s^1$

Electroni configuration of $V^{+1}=\left[Ar\right]3d^{3}4s^1$

Electroni configuration of ${Cr}^{+1}=\left[Ar\right]3d^5$

Electroni configuration of ${Mn}^{+1}=\left[Ar\right]3d^{5}4s^1$

Hence ${Cr}^{+1}$ does not contains electrons in $4s$ subshells.