$\begin{array} {ll}
\text{Element} & \text{Electron Configuration}\\
(1)\; V & a. \; 4s^13d^{10}\\
(2)\; Cr & b. \; 4s^23d^{3}\\
(3)\; Cu & c. \; 3d^1 4s^2 \\
(4)\; Sc & d. 4s^13d^5
\end{array}$
$\begin {array} {1 1} (1) \rightarrow b; \quad (2) \rightarrow a; \quad (3) \rightarrow c; \quad (4) \rightarrow d \\ (1) \rightarrow b; \quad (2) \rightarrow d; \quad (3) \rightarrow a; \quad (4) \rightarrow c \\ (1) \rightarrow a; \quad (2) \rightarrow c; \quad (3) \rightarrow d; \quad (4) \rightarrow b \\ (1) \rightarrow d; \quad (2) \rightarrow c; \quad (3) \rightarrow a; \quad (4) \rightarrow b \end {array}$
