Why is $_{21}Sc$ not considered a transition element?

Niobium and tantalum metals are used in making surgical instruments because they are

What is the number of electrons present in the $d$-subshell if the atomic number is $27$ and the oxidation state is $+2$?

The $I.P.$ values of $Cr, Zn, Mn$,and $Hg$ are $7.4 \ eV, 6.7 \ eV, 10.4 \ eV$,and $9.3 \ eV$. These $I.P.$ values are not listed in the order of the elements. Identify the correct $I.P.$ value for the given elements.

Why are the $E^o$ values for $Mn^{2+}/Mn$,$Zn^{2+}/Zn$,and $Ni^{2+}/Ni$ more negative than expected? The table below provides the values:
| $E^o_{Mn^{2+}/Mn}$ | $E^o_{Zn^{2+}/Zn}$ | $E^o_{Ni^{2+}/Ni}$ |
| :--- | :--- | :--- |
| $-1.18 \ V$ | $-0.76 \ V$ | $-0.25 \ V$ |

Match the following atoms/ions with their correct electronic configurations:

Atom/Ion	Electronic Configuration
$(1) \ Cu$	$(A) 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^{10}$
$(2) \ Cu^{2+}$	$(B) 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^{10}, 4s^2$
$(3) \ Zn^{2+}$	$(C) 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^{10}, 4s^1$
$(4) \ Cr^{3+}$	$(D) 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^9$
	$(E) 1s^2, 2s^2, 2p^6, 3s^2, 3p^6, 3d^3$