The lanthanide contraction is responsible for the fact that:

1. Zr and Y have about the same radius .

2. Zr and Zn have the same oxidation state.  

3. Zr and Hf have about the same atomic radius .

4. Zr and Nb have a similar oxidation state.

Actinoids show a greater number of oxidation states than lanthanoids because:  

Match the following characteristics to the appropriate metal:  

Select the correct option :

The calculated spin-only magnetic moment of Cr²⁺ ion is:

Urea reacts with water to form A, which decomposes to form B. When B is passed through ${\mathrm{Cu}}^{2+}$ (aq), a deep blue-colored solution C is formed

The formula of C is: 

1. ${\left[\mathrm{Cu}{\left({\mathrm{NH}}_3\right)}_4\right]}^{2+}$

2. $\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$

3. ${\mathrm{CuCO}}_3.\mathrm{Cu}{\left(\mathrm{OH}\right)}_2$

4. ${\mathrm{CuSO}}_4$

The incorrect statement among the following is: 

The oxidation state of chromium in the final product formed by the reaction between KI and acidified potassium dichromate solution will be:

1. +2

2. +3

3. +4

4. +6

What is produced when excessive diluted nitric acid is combined with potassium chromate?

1. Cr₂O₇^2- and H₂O  

2. Cr³⁺ and Cr₂O₇^2-  

3. CrO₄^2-  

4. Cr₂O₄^2-  

The magnetic moment of an Mn²⁺ ion is equal to:

Which of the following has the highest negative $\left(\raisebox{1ex}{${\mathrm{M}}^{2+}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{M}$}\right.\right)$ standard electrode potential ?

1. Ti

2. Cu

3. Mn

4. Zn