MCQs Assignment No - 1 d & f – Block Elements | Class 12th

MCQs

Assignment – 1

d & f – Block Elements

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Que 1. Four successive members of the first-row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionisation enthalpy?

a. Vanadium (Z = 23)                         b. Chromium (Z = 24)                                               

c. Manganese (Z = 25)                       d. Iron (Z = 26)

Que 2. The aqueous solution containing which one of the following ions will be colourless?  

 a. Sc³⁺                        b. Fe²⁺                         c. Ti³⁺                         d. Mn²⁺

(Atomic number: Sc = 21, Fe = 26, Ti = 22, Mn = 25)

Que 3. Which one of the following elements with the following outer orbital configuration may exhibit the largest number of oxidation states?

      a.  3d² 4s²                         b. 3d³4s²                     c. 3d⁵4d¹                     d. 3d⁵4s²

Que 4. Which one of the following ions has electronic configuration [Ar] 3d⁶?

a. Co³⁺            b. Ni³⁺             c. Mn³⁺           d. Fe³⁺

Que 5. Transition elements have the maximum tendency to form complexes because

a. they are metals and all metals form complexes

b. they contain incompletely filled d-orbitals

c. their charge/size ratio is quite large

d. of both (b) and (c)

Que 6. In a transition series, as the atomic number increases, paramagnetism

a. increases gradually                                    

b. decreases gradually

c. first increases to a maximum and then decreases                                                              

d. first decreases to a minimum and then increases

Que 7. Which of the following transition metal ions will have definite value of magnetic moment?

a. Sc³⁺                         b. Ti³⁺                          c. Cu⁺                          d. Zn²⁺

Que 8. Cuprous ion is colourless, while cupric ion is coloured because

a. both have unpaired electrons in the d-orbital

b. cuprous ion has a complete d-orbital and cupric ion has an incomplete d-orbital

c. both have half-filled p- and d-orbitals

d. cuprous ion has incomplete d-orbital and cupric ion has a complete d-orbital

Que 9. Amongst TiF₆^2-, CoF₆^3-, Cu₂Cl₂ and NiCl₄^2- (At. Nos. Ti = 22, Co = 27, Cu = 29, Ni = 28). The colourless species are

a. CoF₆^3- and NiCl₄^2-                                                   b. TiF₆^2- and CoF₆^3-                                              

c. Cu₂Cl₂ and NiCl₄^2-                                                  d. TiF₆^2- and Cu₂Cl₂

Que 10. The magnetic moment of a transition metal of 3d-series is 6.92 B.M. Its electronic configuration would be

a. 3d⁵ 4s²                                                         b. 3d⁵ 4s¹

c. 3d⁶ 4s⁰                                                         d. 3d⁵ 4s⁰

Que 11. The first ionization enthalpy of elements of 5d-series are higher than those of 3d- and 4dseries. This is because

a. the atomic radii of elements of 5d-series are smaller than those of 3d- and 4d-series

b. the nuclear charges of elements of 5d-series are higher than those of 3d- and 4d-series

c. the valence shell electrons of 5d elements experience greater effective nuclear charge than 3d- and 4d-elements due to poor shielding of 4f subshell electrons

d. there is appreciable shielding of 4f-subshell electrons on valence shell electrons of 5d elements.

Que 12. Which one of the following shows highest magnetic moment?

a. V³⁺                                      b. Cr³⁺                         c. Fe³⁺                         d. Co³⁺

Que 13. The transition elements are more metallic than the representative elements because they have

a. the electrons in d-orbitals                                       b. electron pairs in d-orbitals

c. availability of d-orbitals for bonding                      d. unpaired electrons in metallic orbitals

Que 14. Colour in transition metal compounds is attributed to

a. small sized metal ions                                             b. absorption of light in UV region

c. complete ns subshell                                               d. incomplete (n-1) d subshell

Que 15. Among the following outermost configurations of transition metals which shows the highest oxidation state?

a. 3d³4s²                                                                      b. 3d⁵4s¹

c. 3d³4s²                                                                      d. 3d⁶4s²

Que 16. In which of the following ions, d-d transition is not possible?

a. Ti⁴⁺                                      b. Cr³⁺                         c. Mn²⁺                        d. Cu²⁺

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