Identify the incorrect statement among the following:

1.	There is a decrease in the radii of the atoms or ions as one proceeds from La to Lu.
2.	Lanthanoid contraction is the accumulation of successive shrinkages
3.	As a result of lanthanoid contraction, the properties of the 4d series of the transition elements have no similarities with the 5d series of elements
4.	The shielding power of 4f electrons is quite weak.

Which one of the following ions is the most stable in an aqueous solution? 
(At. No. Ti = 22, V = 23, Cr = 24, Mn = 25)

1. \(\text{Cr}^{3 +}\)

2. \(\text V^{3 +}\)

3. \(\text{Ti}^{3 +}\)

4. \(\text{Mn}^{3 +}\)

Which one of the elements with the following outer orbital configurations may exhibit the largest number of oxidation states?

1. 3d³, 4s²

2. 3d⁵, 4s¹

3. 3d⁵, 4s²

4. 3d², 4s²

Which of the following pairs has the same size?

1. $F{e}^{2+},$ $N{i}^{2+}$

2. $Z{r}^{4+},$ $T{i}^{4+}$

3. $Z{r}^{4+},$ $H{f}^{4+}$

4. $Z{n}^{2+},$ $H{f}^{4+}$

Which one of the following ions has electronic configuration [Ar] 3d⁶? 
(At. no :Mn = 25, Fe= 26, Co= 27, Ni = 28)

1. $N{i}^{3+}$

2. $M{n}^{3+}$

3. $F{e}^{3+}$

4. $C{o}^{3+}$

Which of the following ions will exhibit colour in aqueous solutions?

1. La³⁺ (Z=57)

2. Ti³⁺ (Z=22)

3. Lu³⁺ (Z=71)

4. Sc³⁺ (Z=21)

Acidified K₂Cr₂O₇ solution turns green when Na₂SO₃ is added to it. This is due to the formation of:

1.  ${\mathrm{CrO}}_4^{2-}$

2.  ${\mathrm{Cr}}_2{\left({\mathrm{SO}}_3\right)}_3$

3.  ${\mathrm{CrSO}}_4$

4.  ${\mathrm{Cr}}_2{\left({\mathrm{SO}}_4\right)}_3$

1.  Fe>Mn>Co>Cr

2.  Co>Mn>Fe>Cr

3.  Cr>Mn>Co>Fe

4.  Mn>Fe>Cr>Co

Which of the following statements is false?