D & F block Questions - CBSE Sample Paper PDF

## CBSE Sample Question Paper ### Which of the following is **not** considered a transition element? - **A) Scandium** - B Silver - C Vanadium - **D Zinc** ### The last electron which enters the atom of transition element is: - A) s-electron - B p-electron - C) f-electron - **D) d-electron** #...

## CBSE Sample Question Paper ### Which of the following is **not** considered a transition element? - **A) Scandium** - B Silver - C Vanadium - **D Zinc** ### The last electron which enters the atom of transition element is: - A) s-electron - B p-electron - C) f-electron - **D) d-electron** ### The transition element with the lowest atomic number is: - **A Scandium (21)** - B Titanium - C Zinc - D Lanthanum ### QUESTION- Example 8.1 On what ground can you say that scandium (Z = 21) is a transition element but zinc (Z = 30) is not? - **Sc** **Sc21** (Ar) 4s² 3d¹ - **Zn** **Zn30** (Ar) ​4s² ​3d¹⁰ **Solution:** On the basis of incompletely filled 3d orbitals in case of scandium atom in its ground state (3d¹), it is regarded as a transition element. On the other hand, zinc atom has completely filled d-orbit (3d¹⁰) in its ground state as well ### QUESTION- Intext Question Silver atom has completely filled d-orbitals (4d¹⁰) in its ground state. How can you say that it is a transition element? - **Ag** 5s¹ 4d¹⁰ **Ag2+** 5s⁰ 4d⁹ ### QUESTION- Chromium has the electronic configuration: - A) 3s² 3p⁶ 3d⁴, 4s² - **B 3s² 3p⁶ 3d⁵, 4s¹** - C) 3s² 3p⁶ 3d⁶ - D) none of these ### QUESTION- The number of d electrons in Fe²⁺ (at no. of iron = 26) is equal to: - A 5 - B) 2 - C 4 - **D 6** - **Fe26** 4s² 3d⁶ - **Fe²⁺** 4s⁰ 3d⁶ ### QUESTION- The maximum number of unpaired electrons are in: - **A Fe²⁺** 4s⁰ 3d⁶ n = 4 - **B Fe³⁺** 4s⁰ 3d⁵ n = 5 - C Fe⁴⁺ 4s⁰ 3d⁴ n = 4 - D Fe 4s² 3d⁶ n = 4 ### QUESTION- Which of the following has the maximum number of unpaired d electrons? - A Zn 30 → 4s² 3d¹⁰ n = 0 - **B Fe²⁺** 4s⁰ 3d⁶ n = 4 - C Ni³⁺ n = 5 - D Cu⁺ 4s⁰ 3d¹⁰ n = 3 ### QUESTION- The electronic configuration of copper is: - A) [Ar] 3d⁹, 4s² - **B) [Ar] 3d¹⁰, 4s¹** - C) [Ar] 3d⁸, 4s² - D [Ar] 3d¹⁰, 4s² ### QUESTION- Which one of the following is the correct configuration of Fe³⁺ (Z = 26)? - A) [Ar] 4s², 3d⁶ - B [Ar] 4s², 3d³ - **C) [Ar] 3d⁵** - D [Ar] 4s², 3d⁴ - Fe26 4s² 3d⁶ - Fe³⁺ 4s⁰ 3d⁵ ### QUESTION- The electronic configuration, 1s² 2s², 2p⁶, 3s², 3p⁶ 3d⁶ corresponds to: - A Mn²⁺ - B Cr³⁺ - **C Fe²⁺ 24 → Fe26 4s² 3d⁶ ** - D Fe³⁺ ### QUESTION- Number of electron in 5S in electronic configuration of Pd is - A) 1 - B 2 - **C 0 ** - D None of these - Pd 5s⁰ 4d¹⁰ ### QUESTION-NCERT Exemplar 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. ### QUESTION- CBSE Sample Question Paper Which of the following options give the correct arrangement of the atomic radii of the 3d, 4d, and 5d transition series of elements? - A) Atomic radii of 3d < atomic radii of 4d < atomic radii of 5d - **B Atomic radii of 3d < atomic radii of 4d = atomic radii of 5d** - C) Atomic radii of 3d = atomic radii of 4d > atomic radii of 5d - D Atomic radii of 3d > atomic radii of 4d > atomic radii of 5d ### QUESTION-NCERT Exemplar Metallic radii of some transition elements are given below. Which of these elements will have highest density? | Element | Metallic radii/pm | |---|---| | Fe | 126 | | Co | 125 | | Ni | 125 | | Cu | 128 | - A Fe - B Ni - C Co - **D Cu** ### QUESTION- In which of the following metallic bond is strongest? - A V - B Fe - **C Cr** - D Sc ### QUESTION- Example 8.2 Why do the transition elements exhibit higher enthalpies of atomisation? **Solution:** Because of large number of unpaired electrons in their atoms, they have stronger interatomic interaction and hence stronger bonding between atoms resulting in higher enthalpies of atomisation. ### QUESTION- Intext Question In the series Sc (Z = 21) to Zn (Z = 30), the enthalpy of atomisation of zinc is the lowest, i.e., 126 kJ mol-1. Why? - **Zn30** (Ar) 4s² 3d¹⁰ no. of unpaired n = 0 EA lowest ### QUESTION- The correct order of decreasing second ionisation enthalpy of Ti (22), V(23), Cr(24) and Mn(25) - A Mn > Cr > Ti > V - B Ti > V > Cr > Mn - **C Cr > Mn > V > Ti ** - D V > Mn > Cr > Ti ### QUESTION- CBSE Sample Question Paper The trend of which property is represented by the following graph? | Element | Radius / pm | |---|---| | Sc | 16 | | Ti | 14.6 | | V | 13.2 | | Cr | 12.7 | | Mn | 12.6 | | Fe | 12.4 | | Co | 12.5 | | Ni | 12.4 | | Cu | 12.8 | | Zn | 13.3 | - **(A) ionization enthalpy ** - **(B) atomic radii** - **(C) enthalpy of atomization** - **(D) melting point** ### QUESTION-NCERT Exemplar In the form of dichromate, Cr (VI) is a strong oxidising agent in acidic medium but Mo (VI) in M003 and W (VI) in WO3 are not because: - A) Cr (VI) is more stable than Mo(VI) and W(VI). - **B Mo(VI) and W(VI) are more stable than Cr(VI)** - C Higher oxidation states of heavier members of group-6 of transition series are more stable. - D Lower oxidation states of heavier members of group-6 of transition series are more stable. ### QUESTION-NCERT Exemplar Which of the following will not act as oxidizing agents? - **A CrO3** - B M003 - C WO3 - D CrO42- ### QUESTION- CBSE SQP 2021 Which of the following is the reason for zinc not exhibiting variable oxidation state? - A Inert pair effect - **B Completely filled 3d-subshell** - C Completely filled 4s-subshell - D Common ion effect - **Zn²⁺** 4s⁰ 3d¹⁰ ### QUESTION- Among the following outermost configurations of transition metals, which shows the highest oxidation state? - A) 3d⁵ 4s¹ - B 3d³ 4s² - **C 3d⁵ 4s²** - D 3d⁶ 4s² ### QUESTION- The most stable oxidation state of Fe is - A +2 - B) +4 - **C +3** - D +5 - Fe²⁺ < Fe³⁺ ### QUESTION- Which one of the following does not show variable oxidation states? - **A Iron** - **B Copper** - **C Zinc** - **D Manganese** ### QUESTION- Which one of the following transition metals shows highest oxidation states? - A Sc - B Ti - **C Os** - D Zn - **Os** → +8 ### QUESTION- Example 8.3 Name a transition element which does not exhibit variable oxidation states. **Solution:** Scandium (Z = 21) does not exhibit variable oxidation states. ### QUESTION- Intext Question Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why? - **Mn** 4s² 3d⁵ → +7 ### QUESTION- CBSE Sample Question Paper Study the graph given below. Observed and calculated values for the standard Electrode potentials (M²+ → M°) of the elements Ti to Zn. | Element | Standard electrode potential/V | |---|---| | Ti | -1.63 | | V | -1.18 | | Cr | -0.74 | | Mn | -1.18 | | Fe | -0.44 | | Co | -0.28 | | Ni | -0.25 | | Cu | +0.34 | | Zn | -0.76 | Based on the graph given, which element will _MOST LIKELY_ be in following reaction? Metal + conc. Sulphuric acid → Metal sulphate + sulphur dioxide + water - A Cu - B Co - **C Ti** - D Zn ### QUESTION- Delhi 2020, All India 2020, 2017C BSE Explain the following observation: (i) Copper atom has completely filled d-orbitals (3d¹⁰) in its ground state, yet it is regarded as a transition element. (ii) Cr²⁺ is a stronger reducing agent than Fe²⁺ in aqueous solutions. ### QUESTION- Example 8.4 Why is Cr²⁺ reducing and Mn³⁺ oxidising when both have d⁴ configuration? **Solution:** Cr²⁺ is reducing as its configuration changes from d⁴ to d³, the latter having a half-filled t₂g leave. On the other hand, the change from Mn³⁺ to Mn²⁺ results in the half-filled (d⁵) configuration which has extra stability. ### QUESTION- Intext Question The E/ (M²⁺/M) value for copper is positive (+0.34 V). What is possible reason for this? (Hint: Consider its high ∆₂H® and low ∆hydH®) - E⁰ Cu²⁺/Cu → high ionization ### QUESTION-NCERT Exemplar 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 form single bond only while oxygen forms double bond.** ### QUESTION- Example 8.5 How would you account for the increasing oxidation power in the series VO2+ < Cr2O72- < MnO4- ? **Solution:** This is due to the increasing stability of the lower species to which they are reduced. ### QUESTION- Intext Question How would you account for the irregular variation of ionisation enthalpies (first and second) in the first series of the transition element? ### QUESTION- Example 8.6 For the first row transition metals the E® values are: | Element | Eº (M²⁺/M) | |---|---| | V | -1.18 | | Cr | -0.91 | | Mn | -1.18 | | Fe | -0.44 | | Co | -0.28 | | Ni | -0.25 | | Cu | +0.34 | Explain the irregularity in the above values. **Solution:** The E® (M²⁺/M) values are not regular which can be explained from the irregular variation of ionisation enthalpies (Δ₄H₁ + Δ₁H₂) and also the sublimation enthalpies which are relatively much less for manganese and vanadium. ### QUESTION- Example 8.7 Why is the E- value for the Mn³⁺/Mn²⁺ couple much more positive than that for Cr³⁺/Cr²⁺ or Fe³⁺/Fe²⁺? Explain **Solution:** Much larger third ionisation energy of Mn (where the required change is d⁵ to d⁴) is mainly responsible for this. This also explains why the +3 state of Mn is of little importance. ### QUESTION- Intext Question Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only? - Mn₂O₇ → +7 ### QUESTION- Intext Question Which is a stronger reducing agent Cr²⁺ or Fe²⁺ and why? ### QUESTION- Example 8.9 What is meant by 'disproportionation' of an oxidation state? Given an example. **Solution:** When a particular oxidation state becomes less stable relative to other oxidation states, one lower, one higher, it is said to undergo disproportionation. For example, manganese (VI) becomes unstable relative to manganese (VII) and manganese (IV) in acidic solution. 3MnVIO2- + 4H+ → 2MnVIIO4 + MnVO2 + 2H2O ### QUESTION- Intext Question Explain why Cu⁺ ion is not stable in aqueous solutions? - Cu⁺ → Cu²⁺ + Cu - Cu⁺HE > Cu²⁺HE ### QUESTION-CBSE SQP 2021 Which of the following is a diamagnetic ion (atomic numbers of Cs, V, Mn and Cu are 21, 23, 25 and 29 respectively) - A V²⁺ - **B Sc³⁺** 4s⁰ 3d⁰ n = 0 - C Cu²⁺ n = 0 - D Mn³⁺ ### QUESTION- Example 8.8 Calculate the magnetic moment of a divalent ion in aqueous solution if its atomic number is 25. **Solution:** With atomic number 25, the divalent ion in aqueous solution will have d⁵ configuration (five unpaired electrons). The magnetic moment, μ is μ = √5(5 + 2) = 5.92 BM ### QUESTION- Intext Question Calculate the 'spin only' magnetic moment of M²⁺(aq) ion (Z = 27). - Co²⁺ 4s⁰ 3d⁷ n = 3 - μ = √3 x 5 - = √15 = 3.87 BM ### QUESTION- The highest magnetic moment is shown by the transition metal ion with the outer electronic configuration - A 3d² n= 2 - B 3d⁷ n= 3 - **C 3d⁵ n = 5** - D 3d⁹ ### QUESTION- Which of the following has highest magnetic moment? - A Ti³⁺ 4s⁰ 3d¹ n=1 - B Sc³⁺ 4s⁰ 3d⁰ n= 0 - **C Mn²⁺ 4s⁰ 3d⁵ n= 5** - D Zn²⁺ → 4s⁰ 3d¹⁰ n = 0 ### QUESTION- Electrons in a paramagnetic compound are - **A unpaired** - B shared - C paired - D donated ### QUESTION- Which of the following has lowest magnetic moment - A 3d² n = 2 - B 3d⁷ n = 3 - **C 3d⁹ n = 1** - D 3d³ ### QUESTION- Which of the following ions has the least magnetic moment? - **A Cu²⁺** 4s⁰ 3d⁹ n = 1 - B Ni²⁺ 4s⁰ 3d⁸ - C Co³⁺ 4s⁰ 3d⁶ n = 4 - D Fe²⁺ 4s⁰ 3d⁶ n= 4 ### QUESTION- Which one of the following sets correctly represents the increase in the paramagnetic property of the ions? - A Cu²⁺ > V²⁺ > Cr²⁺ > Mn²⁺ - B Cu²⁺ < Cr²⁺ < V²⁺ < Mn²⁺ - **C Cu²⁺ > V²⁺ > Cr²⁺ < Mn²⁺** - D V²⁺ < Cu²⁺ < Cr²⁺ < Mn²⁺ ### QUESTION- The substance will be coloured if - **A) it absorbs certain wavelengths from white light.** - B d-d transitions are permissible - C all electrons in 3d orbitals in its ion are paired - **D) both (A) and (B)** ### QUESTION- Which ion gives coloured solution? - A) Cu1+ 4s⁰ 3d¹⁰ n= 0 - B Zn²⁺ 4s⁰ 3d¹⁰ n = 0 - C Ag1+ - **D Fe²⁺ 4s⁰ 3d⁶ n= 4** ### QUESTION- Which one of the following ions is colourless? - A Mn³⁺ - B V³⁺ - C Ni²⁺ - **D Zn²⁺ 4s⁰ 3d¹⁰ n = 0 ** ### QUESTION- In which of the following pairs are both ions are coloured in aqueous solution? - A Sc³⁺, Ti³⁺ - B Sc³⁺ Co²⁺ - C Ni²⁺, Cu²⁺ - **D Ni²⁺, Ti³⁺** ### QUESTION- Which of the following set has all the coloured ions - A Cu⁺, Cu²⁺, Ni²⁺ - B Cu²⁺, Co²⁺, Sc³⁺ - **C Cu²⁺, Fe²⁺, Co²⁺ ** - D Na⁺, Mg²⁺, Al³⁺ ### QUESTION- CBSE Sample Question Paper Match the properties with the elements of 3d series: - (i) lowest enthalpy of atomization - (ii) shows maximum number of oxidation states - (iii)transition metal that does not form coloured compounds | Property | Element | |---|---| | (i) | (r) Zn | | (ii) | (q) Mn | | (iii) | (p) Sc | ### QUESTION- The _catalytic activity_ of the transition metals and their compounds is ascribed to their - A magnetic behaviour - B chemical reactivity - C unfilled d-orbitals - **D ability to adopt multiple oxidation states and their complexing ability** ### QUESTION- In the manufacture of H2SO4 by contact process, the catalyst used is/are - A Pt - B MnO2 - **C V2O5 ** - D both Ni and Pd ### QUESTION- All India 2020, NCERT Exemplars Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals Which of the following is **not** the characteristics property of interstitial compounds? - **A) They have high melting points in comparison to pure metals** - B They are very hard - C They retain metallic conductivity - D The are chemically very reactive ### QUESTION- (CBSE 2023) Assign reason for each of the following : - (i) Manganese exhibits the highest oxidation state of +7 among the 3d series of transition elements. - (ii) Transition metals and their compounds are generally found to be good catalysts in chemical reactions. - (iii) Cr²⁺ is reducing in nature while with the same d-orbital configuration (d⁴) Mn³⁺ is an oxidising agent. - (iv) Zn has lowest enthalpy of atomization. - (v) Cu⁺ is unstable in an aqueous solution. ### QUESTION- 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 - **A Mn₂O₇** - B MnO2 - C MnSO4 - D Mn₂O3 ### QUESTION- In dichromate dianion, - A 4 Cr-O bonds are equivalent - **B 6 Cr-O bonds are equivalent** - C all Cr-O bonds are equivalent - D all Cr-O bonds are non-equivalent ### QUESTION- (CBSE 2023) Complete the following equations : - (a) 2MnO4- + 5NO2 + 6H+ → 2Mn²+ + 5NO3- + 3H2O - (b) Cr2O72- + 14H+ + 6e- → 2Cr³⁺ + 7H2O ### QUESTION- The total number of elements present in fblock of the periodic table is - A 20 - ** B 28** - C 30 - D 26 ### QUESTION- 1st element of Lanthanides and Actinides are respectively - A La, Ce - **B Ce, Th** - C Ac, La - D La, Ac ### QUESTION- The last element in Lanthanides and Actinides are - A La, Ac - B Ce, Th - **C Lu, Lr** - D Th, Lr ### QUESTION- Lutetium and Lawrencium are - A Actinide and Lanthanide respectively - **B Lanthanide and Actinide respectively** - C Both Actinides - D Both Lanthanides ### QUESTION- Atomic number of Einstenium is - A 96 - B 97 - **C 98** - D 99 - ** Th Pa U Np Pu Am Cm Bk Cf Es** - **90 91 92 93 94 95 96 97 98 99** ### QUESTION- The electronic configuration of gadolinium (At. No. 64) is - A [Xe] 4f⁸ 5d⁰ 6s² - **B) [Xe] 4f⁷ 5d¹ 6s²** - C [Xe] 4f³ 5d⁵ 6s² - D [Xe] 4f⁶ 5d² 6s² - **Gd** 6s² 5d¹ 4f⁷ ### QUESTION- The number of 4f electrons in Eu (63) and Gd (64) are - A 6, 7 - B 7, 6 - **C 7, 7** - D 6, 6 ### QUESTION- Electronic configuration of Lawrencium is - A 5f¹⁴ 6d² 7s² - **B 5f¹⁴ 6d¹ 7s²** - C 5f¹³ 6d² 7s² - D 5f¹⁴ 6d³ 7s⁰ - **Lr** 7s² 6d¹ 5f¹⁴ ### QUESTION- Which actinoid does not have any electron in 5f-subshell? - **A Ac(z = 89)** - B Th(z = 90) - C Pa(z = 91) - D All of these - **Th** 7s² 6d¹ 5f⁰ ### QUESTION- Which element among the lanthanides has the smallest atomic radius? - A Cerium - **B Lutetium** - C Europium - D Gadolinium ### QUESTION- The radius of La³⁺ (At. No. of La = 57) is 1.06 Å. Which one of the following given values will be closet to the radius of Lu³⁺ (At. No. of Lu = 71) - A 1.40 Å - B 1.06 Å - **C 0.85 Å** - D 1.60 Å - **Lu³⁺** 6s⁰ 5d⁰ 4f¹⁴ ### QUESTION- (CBSE 2023) The most common oxidation state of lanthanides is - A +4 - **B +3** - C +6 - D +2 ### QUESTION- Most common oxidation states shown by Ce are - A +2, +4 - **B +3, +4 ** - C +3, +5 - D +2, +3 ### QUESTION- Choose the correct statement - A Eu(63) exhibits +2 oxidation state - B Yb(70) exhibits +2 oxidation state - C Ce(58) exhibits +4 oxidation state - **D all of these** ### QUESTION- The reason for the stability of Gd³⁺ ion is - **A) 4f-subshell-half filled.** - B 4f subshell – completely filled - C possesses the general electronic configuration of noble gases - D 4f subshell-empty - **Gd** 6s² 5d¹ 4f⁷ - **Gd³⁺** 6s⁰ 5d⁰ 4f⁷ ### QUESTION- The bonds in compounds of Lanthanides are - A covalent - **B ionic** - C coordinate covalent - D metallic ### QUESTION- Example (8.10) Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state. **Solution:** Cerium (Z = 58) ### QUESTION- Intext Question Actinoid contraction is greater from element to element than lanthanoid contraction. Why ### QUESTION- Which elements are called transuranics? - A elements of 1st and 2nd group - B elements of 4d & 5d series - **C elements after atomic number 92** - D elements of actinide series, prior to uranium ### QUESTION- CBSE Sample Question Paper Answer any five questions with respect to the series of ions given below : Sc+3, Ti+4, V+4, V+2, Cr+2, Fe+3, Ni+2, Cu+2, Zn+2 (a) Which of these ions are isoelectronic? (b) Why do Sc+3, Ti+4 and Zn+2 form colourless aqueous solution? (c) Which ion(s) from the list is/are not transition element(s) and why? (d) Cr forms two types of oxides – Cr+2 and Cr+3. Which of them is expected to turn red litmus blue? (e) Arrange the following ions in the increasing order of their magnetic moments : Sc+3, V+2, V+4, Ni+2. (f) Why are alloys mostly prepared from transition metals? (g) Which ion can also has a +1 oxidation state ? [Atomic number of : Sc = 21, Ti = 22, V = 23, Cr = 24, Fe = 26, Ni = 28, Cu = 29, Zn = 30]