Electronic configuration of a transition element X in +3 oxidation state is [Ar]3d⁵. What is its atomic number? (a) 25 (b) 26 (c) 27 (d) 24

The electronic configuration of Cu(II) is 3d⁹ whereas that of Cu(I) is 3d¹⁰. Which of the following is correct? (a) Cu(II) is more stable (b) Cu(II) is less stable (c) Cu(I) and Cu(II) are equally stable (d) Stability of Cu(I) and Cu(II) depends on nature of copper salts

Metallic radii of some transition elements are given below. Which of these elements will have highest density?

When KMnO₄ solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because (a) CO₂ is formed as the product. (b) The reaction is exothermic. (c) MnO₄⁻ catalyses the reaction. (d) Mn²⁺ acts as an auto-catalyst.

The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Spin only magnetic moment value of Cr³⁺ ion is (a) 2.87 BM (b) 3.87 BM (c) 3.47 BM (d) 3.57 BM

Although Zirconium belongs to 4d transition series and Hafnium to 5d transition series even then they show similar physical and chemical properties because (a) both belong to d-block. (b) both have same number of electrons. (c) both have similar atomic radius. (d) both belong to the same group of the periodic table.

Highest oxidation state of manganese in fluoride is +4 (MnF₄) but highest oxidation state in oxides is +7 (Mn₂O₇) because (a) fluorine is more electronegative than oxygen. (b) fluorine does not possess d-orbitals. (c) fluorine stabilises lower oxidation state. (d) in covalent compounds fluorine can formsingle bond only while oxygen forms double bond.