Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d⁵ .What is its atomic number?

1. 25

2. 26

3. 27

4. 24

The electronic configuration of Cu(II) is 3d⁹ whereas that of Cu(I) is 3d¹⁰. Which of the following is correct?

1. Cu(II) _aq is more stable

2. Cu(II) _aq is less stable

3. Cu(I) _aq and Cu(II)  _aq are equally stable

4. Stability of Cu(I) _aq and Cu(II) _aq depends on nature of copper salts

Generally transition elements form coloured salts due to the presence of unpaired electrons. Which of the following compounds will be coloured in solid state?

1. Ag₂SO₄

2. CuF₂

3. ZnF₂

4. Cu₂Cl₂

On addition of small amount of KMnO₄ to concentrated H₂SO₄, a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following.

1. Mn₂O₇

2. MnO₂

3. MnSO₄

4. Mn₂O₃

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.

1. 3d⁷

2. 3d⁵

3. 3d⁸

4. 3d²

The oxidation state common for all lanthanoids is:

1. +2

2. +3

3. +4

4. +5

When KMnO₄ solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because

1. CO₂ is formed as the product.

2. Reaction is exothermic.

3. MnO₄^– catalyses the reaction.

4. Mn²⁺ acts as autocatalyst.

There are 14 elements in actinoid series. Which of the following elements does not belong to this series?

1. U

2. Np

3. Tm

4. Fm

Identify the amphoteric oxides from the list provided:

${\mathrm{Mn}}_2{\mathrm{O}}_7, {\mathrm{CrO}}_3, {\mathrm{Cr}}_2{\mathrm{O}}_3, \mathrm{CrO}, {\mathrm{V}}_2{\mathrm{O}}_5, {\mathrm{V}}_2{\mathrm{O}}_4$

1. ${\mathrm{V}}_2{\mathrm{O}}_5, {\mathrm{Cr}}_2{\mathrm{O}}_3$

2. ${\mathrm{Mn}}_2{\mathrm{O}}_7, {\mathrm{CrO}}_3$

3. $\mathrm{CrO}, {\mathrm{V}}_2{\mathrm{O}}_5$

4. ${\mathrm{V}}_2{\mathrm{O}}_5, {\mathrm{V}}_2{\mathrm{O}}_4$

Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds?

1. They have high melting points in comparison to pure metals.

2. They are very hard.

3. They retain metallic conductivity.

4. They are chemically very reactive.