Which d-block elements are not considered transition elements, and why?

1.	Mn, Fe, and Ni because these have partially filled d-subshell.
2.	Mn, Fe, and Ni because these have completely filled d-subshell.
3.	Zn, Cd, and Hg because these have completely filled d-subshell.
4.	Zn, Cd, and Hg because these have partially filled d-subshell.

The different oxidation states exhibited by the lanthanoids are:

The "Disproportionation" reaction means that :

In the 3d series, a metal with a +1 oxidation state is:

The number of unpaired electrons in the gaseous ions ${\mathrm{Mn}}^{3+},$ ${\mathrm{Cr}}^{3+},$ ${\mathrm{V}}^{3+,}$ $\mathrm{and}$ ${\mathrm{Ti}}^{3+ }$ are, respectively:

Alloy that contains lanthanoid metals is-

Give below are some atomic numbers:

29, 59, 74, 95, 102, 104
The atomic numbers of the inner transition elements among the above are :

The electronic configuration of the last element of actinoids is :

1. Thorium, Th: $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{14}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$

2. Lawrencium, Lr: $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{14}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$

3. Neptunium, Np: $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{14}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$

4. Protactinium, Pa: $\left[\mathrm{Rn}\right]5{\mathrm{f}}^{14}6{\mathrm{d}}^{1}7{\mathrm{s}}^2$

The number of 3d electrons in the Cr³⁺ ions will be: