The incorrect statement among the following is:
1.
Zirconium and Hofnium have identical radii of 160 pm and 159 pm, respectively, as a consequence of lanthanoid contraction.
2.
Lanthanoids reveal only a +3 oxidation state.
3.
Lanthanoid ions, other than the f0 type and the f14 type, are all paramagnetic.
4.
The overall decrease in atomic and ionic radii from lanthanum to lutetium is called lanthanoid contraction.
An example of the effect of the concentration of nitric acid on the formation of oxidation products would be:
1. 3Cu + 8HNO3(conc.) → 3Cu(NO3)2 + 2NO + 4H2O
2. Cu + 4HNO3 (conc.) → Cu(NO3)2 + 2NO2 + 2H2O
3. Both (1), and (2)
4. None of the above
Match the following characteristics to the appropriate metal:
| Column I - Aspects | Column II - Metal | ||
| (a) | The metal which reveals the maximum number of oxidation states | (i) | Scandium |
| (b) | The metal although placed in 3d block is considered not as a transition element | (ii) | Copper |
| (c) | The metal which does not exhibit variable oxidation states | (iii) | Manganese |
| (d) | The metal which in +1 oxidation state in aqueous solution undergoes disproportionation | (iv) | Zinc |
Select the correct option :
| (a) | (b) | (c) | (d) | |
| 1. | (i) | (iv) | (ii) | (iii) |
| 2. | (iii) | (iv) | (i) | (ii) |
| 3. | (iii) | (i) | (iv) | (ii) |
| 4. | (ii) | (iv) | (i) | (iii) |
Find the atomic number of a transition element X whose +3 oxidation state has the electronic configuration [Ar] 3d⁵.
1. 25
2. 26
3. 27
4. 24
Among the following, which are amphoteric oxides?
1. V2O5, Cr2O3
2. Mn2O7, CrO3
3. CrO, V2O5
4. V2O5, V2O4
Find the correct value of the spin-only magnetic moment of the Cr³⁺ ion.
| 1. | 2.87 BM | 2. | 3.87 BM |
| 3. | 3.47 BM | 4. | 3.57 BM |
Which of the following statements is false?
| 1. | Copper liberates hydrogen from acids. |
| 2. | In its higher oxidation states, manganese forms stable compounds with oxygen and fluorine. |
| 3. | Mn3+, and Co3+ are oxidizing agents in an aqueous solution. |
| 4. | Ti2+, and Cr2+ are reducing agents in an aqueous solution. |
:
Why does manganese show a maximum oxidation state of +4 in MnF₄ but reach +7 in Mn₂O₇?
| 1. | Fluorine is more electronegative than oxygen. |
| 2. | Fluorine does not possess d orbitals. |
| 3. | Fluorine stabilizes the lower oxidation state of Mn. |
| 4. | In covalent compounds, fluorine forms only single bonds while oxygen can form double bonds. |
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