NEET Chemistry The D and F Block Elements MCQs Set B

Question: Gadolinium belongs to 4f series. Its atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?

• a) [Xe]4f⁷5d¹6s² 
• b) [Xe]4f⁶5d²6s²
• c) [Xe]4f⁸6d² 
• d) [Xe]4f⁹5s¹

Answer:  [Xe]4f⁷5d¹6s² 

Question: Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii?(Numbers in the parenthesis are atomic numbers)

• a) Zr (40) and Ta (73)
• b) Ti (22) and Zr (40)
• c) Zr (40) and Nb (41)
• d) Zr (40) and Hf (72)

Answer: Zr (40) and Hf (72)

Question: Reason of lanthanoid contraction is

• a) Negligible screening effect of 'f' orbitals
• b) Increasing nuclear charge
• c) Decreasing nuclear charge
• d) Decreasing screening effect

Answer: Negligible screening effect of 'f' orbitals

Question: The pair of compounds that can exist together is

• a) FeCl₃, SnCl₂ 
• b) HgCl₂, SnCl₂
• c) FeCl₂, SnCl₂
• d) FeCl₃, KI

Answer: FeCl₂, SnCl₂

Question:  The reaction of aqueous KMnO₄ with H₂O₂ in acidic conditions gives

• a) Mn⁴⁺ and O₂
• b) Mn²⁺ and O₂
• c) Mn²⁺ and O₃  
• d) Mn⁴⁺ and MnO₂

Answer: Mn²⁺ and O₂

Question: Magnetic moment 2.83 BM is given by which of the following ions ? (At. nos. Ti=22, Cr=24, Mn=25, Ni=28)

• a) Ti³⁺
• b) Ni²⁺
• c) Cr³⁺
• d) Mn²⁺

Answer:  Ni²⁺

Question: Reason of lanthanoid contraction is

• a) Negligible screening effect of 'f' orbitals
• b) Increasing nuclear charge
• c) Decreasing nuclear charge
• d) Decreasing screening effect

Answer: Negligible screening effect of 'f' orbitals

Question: Which of the following statements about the interstitial compounds is incorrect ?

• a) They are chemically reactive
• b) They are much harder than the pure metal
• c) They have higher melting points than the pure metal
• d) They retain metallic conductivitiy

Answer: They are chemically reactive

Question: Which of the following lanthanoid ions is diamagnetic? (At nos. Ce=58, Sm=62, Eu=63, Yb=70)

• a) Sm²⁺ 
• b) Eu²⁺
• c) Yb²⁺
• d) Ce²⁺

Answer: Yb²⁺

Question: Which of the statements is not true ?

• a) K₂Cr₂O₇ solution in acidic medium is orange
• b) K₂Cr₂O₇ solution becomes yellow on increasing the pH beyond 7
• c) On passing H₂S through acidified K₂Cr₂O₇ solution, a milky colour is observed
• d) Na₂Cr₂O₇ is preferred over K₂Cr₂O₇ in volumetric analysis

Answer: Na₂Cr₂O₇ is preferred over K₂Cr₂O₇ in volumetric analysis

Question: Which one of the following does not correctly represent the correct order of the property indicated against it ?

• a) Ti < V < Cr < Mn : increasing number of oxidation states
• b) Ti³⁺ < V³⁺ < Cr³⁺ < Mn³⁺ : increasing magnetic moment
• c) Ti < V < Cr < Mn : increasing melting points
• d) Ti < V < Mn < Cr : increasing 2nd ionization enthalpy

Answer: Ti < V < Cr < Mn : increasing melting points

Question: Which of the following exhibits only +3 oxidation state ?

• a) U
• b) Th
• c) Ac
• d) Pa

Answer: Ac

Question:  Four successive members of the first series of the transition metals are listed below. For which one of them the standard potential (E°_M2+/M) value has a positive sign ? 

• a) Co (Z = 27)
• b) Ni (Z = 28)
• c) Cu (Z = 29)
• d) Fe (Z = 26)

Answer: Cu (Z = 29)

Question: For the four successive transition elements (Cr, Mn, Fe and Co), the stability of +2 oxidation state will be there in which of the following order? (At nos. Cr = 24, Mn = 25, Fe = 26, Co = 27)

• a) Cr > Mn > Co > Fe
• b) Mn > Fe > Cr > Co
• c) Fe > Mn > Co > Cr
• d) Co > Mn > Fe > Cr

Answer: Mn > Fe > Cr > Co

More Questions...........................................

Question: Which of the following ions will exhibit colour in aqueous solutions ?

• a) La³⁺ (Z = 57) 
• b) Ti³⁺ (Z = 22)
• c) Lu³⁺ (Z = 71)
• d) Sc³⁺ (Z = 21)

Answer: Ti³⁺ (Z = 22)

Question: Which one of the following ions has electronic configuration [Ar] 3d⁶ ? 

• a) Ni³⁺
• b) Mn³⁺
• c) Fe³⁺
• d) Co³⁺

Answer: Co³⁺

Question: Which of the following pairs has the same size ?

• a) Fe²⁺, Ni²⁺
• b) Zr⁴⁺, Ti⁴⁺
• c) Zr⁴⁺, Hf⁴⁺ 
• d) Zn²⁺, Hf⁴⁺

Answer:  Zr⁴⁺, Hf⁴⁺ 

Question: Which of the following oxidation states is the most common among the lanthanoids ?

• a) 4
• b) 2
• c) 5
• d) 3

Answer: 3

Question: The correct order of decreasing second ionisation enthalpy of Ti(22), V(23), Cr(24) and Mn(25) is

• a) Ti > V > Cr > Mn
• b) Cr > Mn > V > Ti
• c) V > Mn > Cr > Ti
• d) Mn > Cr > Ti > V

Answer: Cr > Mn > V > Ti

Question: Number of moles of MnO₄^– required to oxidize one mole of ferrous oxalate completely in acidic medium will be

• a) 0.2 moles
• b) 0.6 moles
• c) 0.4 moles
• d) 7.5 moles

Answer: 0.6 moles

Question: Identify the incorrect statement among the following

• a) Shielding power of 4f electrons is quite weak
• b) There is a decrease in the radii of the atoms or ions as one proceeds from La to Lu
• c) Lanthanoid contraction is the accumulation of successive shrinkages
• d) As a result of lanthanoid contraction, the properties of 4d series of the transition elements have no similarities with the 5d series of elements

Answer: As a result of lanthanoid contraction, the properties of 4d series of the transition elements have no similarities with the 5d series of elements

Question: More number of oxidation states are exhibited by the actinoids than by the lanthanoids. The main reason for this is

• a) More energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals
• b) Lesser energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals
• c) Greater metallic character of the lanthanoids than that of the corresponding actinoids
• d) More active nature of the actinoids

Answer: Lesser energy difference between 5f and 6d orbitals than that between 4f and 5d orbitals

Question: Which one of the following ions is the most stable in aqueous solution? (Atomic number. Ti = 22, V = 23, Cr = 24,Mn = 25)

• a) Mn²⁺ 
• b) Cr³⁺
• c) V³⁺
• d) Ti³⁺

Answer: Cr³⁺

Question: Copper sulphate dissolves in excess of KCN to give

• a) CuCN
• b) [Cu(CN)₄]^3–
• c) [Cu(CN)₄]^2– 
• d) Cu(CN)₂

Answer:  [Cu(CN)₄]^3–

Question: In which of the following pairs are both the ions coloured in aqueous solution?(At. no.: Sc = 21, Ti = 22, Ni = 28,Cu = 29, Co = 27)

• a) Ni²⁺, Ti³⁺
• b) Sc³⁺, Ti³⁺
• c) Sc³⁺, Co²⁺ 
• d) Ni²⁺, Cu⁺

Answer: Ni²⁺, Ti³⁺

Question:  The number of moles of KMnO₄ reduced one mole of Kl in alkaline medium is 

• a) One fifth
• b) Five
• c) One
• d) Two

Answer: Two

Question: Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them expected to have the highest third ionization enthalpy?

• a) Vanadium (Z = 23)
• b) Chromium (Z = 24)
• c) Iron (Z = 26)
• d) Manganese (Z = 25)

Answer: Manganese (Z = 25)

Question: The main reason for larger number of oxidation states exhibited by the actinides than the corresponding lanthanides, is

• a) Lesser energy difference between 5f and 6d orbitals than between 4f and 5d orbitals
• b) Larger atomic size of actinides than the lanthanides
• c) More energy difference between 5f and 6d orbitals than between 4f and 5d orbitals
• d) Greater reactive nature of the actinides than the lanthanides

Answer: Lesser energy difference between 5f and 6d orbitals than between 4f and 5d orbitals

Question: The aqueous solution containing which one of the following ions will be colourless? (Atomic no. Sc = 21, Fe = 26,Ti = 22, Mn = 25)

• a) Sc³⁺ 
• b) Fe²⁺ 
• c) Ti³⁺ 
• d) Mn²⁺

Answer: Sc³⁺ 

Question: Acidified K₂Cr₂O₇ solution turns green when Na₂SO₃ is added to it. This is due to the formation of

• a) CrSO₄
• b) Cr₂(SO₄)₃
• c) CrO₄^2–  
• d) Cr₂(SO₃)₃

Answer:  Cr₂(SO₄)₃

Question: The catalytic activity of transition metals and their compounds is ascribed mainly to

• a) Their magnetic behaviour
• b) Their unfilled d-orbitals
• c) Their ability to adopt variable oxidation states
• d) Their chemical reactivity

Answer: Their ability to adopt variable oxidation states

Question: Which one of the following elements shows maximum number of different oxidation states in its compounds?

• a) Gd
• b) La
• c) Eu
• d) Am

Answer: Am

Question:  Without losing its concentration ZnCl₂ solution cannot be kept in contact with

• a) Pb
• b) Al
• c) Au
• d) Ag

Answer: Al

Question: Which ion is colourless?

• a) Cr⁴⁺
• b) Sc³⁺ 
• c) Ti³⁺
• d) V³⁺

Answer:  Sc³⁺ 

Question: Which of the following shows maximum number of oxidation states?

• a) Cr
• b) Fe
• c) Mn
• d) V

Answer: Mn

Question:  In the silver plating of copper, K[Ag(CN)₂] is used instead of AgNO₃ . The reason is

• a) A thin layer of Ag is formed on Cu
• b) More voltage is required
• c) Ag⁺ ions are completely removed from solution
• d) Less availability of Ag⁺ ions, as Cu can not displace Ag from [Ag(CN)₂]^– ion

Answer:  Less availability of Ag⁺ ions, as Cu can not displace Ag from [Ag(CN)₂]^– ion

Question: Which of the following is expected to be coloured in solutions?

• a) Cu⁺
• b) Cu²⁺
• c) Ti⁴⁺
• d) Sc³⁺

Answer: Cu²⁺

Question: The basic character of the transition metal monoxides follows the order (Atomic nos. Ti = 22, V = 23,Cr = 24, Fe = 26)

• a) VO > CrO > TiO > FeO
• b) CrO > VO > FeO > TiO
• c) TiO > FeO > VO > CrO
• d) TiO > VO > CrO > FeO

Answer: TiO > VO > CrO > FeO

Question:  CuSO₄ when reacts with KCN forms CuCN, which is insoluble in water. It is soluble in excess of KCN, due to formation of the following complex

• a) K₂[Cu(CN)₄]  
• b) K₃[Cu(CN)₄]
• c) CuCN₂   
• d) Cu[K Cu(CN)₄]

Answer: K₃[Cu(CN)₄]

Question: General electronic configuration of lanthanides is

• a) (n – 2) f^{1 – 14} (n – 1) d^{0 – 1} ns²    
• b) (n – 2) f^{10 – 14} (n – 1) d^{0 – 1} ns²
• c) (n – 2) f^{0 – 14} (n – 1) d¹⁰ ns² 
• d) (n – 2) d^{0 – 1} (n – 1) f^{1 – 14}ns²

Answer: (n – 2) f^{1 – 14} (n – 1) d^{0 – 1} ns²    

Question:  The correct order of ionic radii of Y³⁺, La³⁺, Eu³⁺ and Lu³⁺ is (Atomic nos. Y = 39, La = 57, Eu = 63, Lu = 71) 

• a) Y³⁺ < La³⁺ < Eu³⁺ < Lu³⁺
• b) Y³⁺ < Lu³⁺ < Eu³⁺ < La³⁺
• c) Lu³⁺< Eu³⁺ < La³⁺ < Y³⁺ 
• d) La³⁺< Eu³⁺ < Lu³⁺ < Y³⁺

Answer: Y³⁺ < Lu³⁺ < Eu³⁺ < La³⁺

Question: Which of the following lanthanide ions is diamagnetic?(At. nos. Ce = 58, Sm = 62, Eu = 63, Yb = 70)

• a) Sm²⁺
• b) Eu²⁺
• c) Yb²⁺
• d) Ce²⁺

Answer: Yb²⁺

Question:  Among the following series of transition metal ions, the one where all metal ions have 3d² electronic configuration is [At. Nos. Ti = 22, V = 23, Cr = 24, Mn = 25]

• a) Ti³⁺, V²⁺, Cr³⁺, Mn⁴⁺
• b) Ti⁺, V⁴⁺, Cr⁶⁺, Mn⁷⁺
• c) Ti⁴⁺, V³⁺, Cr²⁺, Mn³⁺
• d) Ti²⁺, V³⁺, Cr⁴⁺, Mn⁵⁺

Answer:   Ti²⁺, V³⁺, Cr⁴⁺, Mn⁵⁺

Question: Lanthanides are

• a) 14 elements in the sixth period (atomic number 90 to 103) that are filling 4f sublevel
• b) 14 elements in the seventh period (atomic number = 90 to 103) that are filling 5f sublevel
• c) 14 elements in the sixth period (atomic number = 58 to 71) that are filling the 4f sublevel
• d) 14 elements in the seventh period (atomic number = 50 to 71) that are filling 4f sublevel

Answer: 14 elements in the sixth period (atomic number = 58 to 71) that are filling the 4f sublevel

Question: Which of the following statement is not correct?

• a) La(OH)₂ is less basic than Lu(OH)₃
• b) In lanthanide series ionic radius of Lu⁺³ ion decreases
• c) La is actually an element of transition series rather lanthanides
• d) Atomic radius of Zr and Hf are same because of lanthanide contraction

Answer:  La(OH)₂ is less basic than Lu(OH)₃

Question:

(Z of Ti = 22, CO = 27, Cu = 29, Ni = 28) the colourless species are

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which of the following ions will exhibit colour in aqueous solutions?

• a) Sc³⁺ (Z = 21)
• b) La³⁺ (Z = 57)
• c) Ti³⁺ (Z = 22)
• d) Lu³⁺ (Z = 71)

Answer: Ti³⁺ (Z = 22)

Question: The highest possible oxidation state shown by osmium in its compound is

• a) +4
• b) +8
• c) +6
• d) +10

Answer: +8

Question: Reason of lanthanoid contraction is

• a) Negligible screening effect of 'f' orbitals
• b) Increasing nuclear charge
• c) Decreasing nuclear charge
• d) Decreasing screening effect

Answer: Negligible screening effect of 'f' orbitals

Question: Which one of the elements with the following outer orbital configurations may exhibit the largest number of oxidations states?

• a) 3d²4s² 
• b) 3d³4s²
• c) 3d⁵4s¹ 
• d) 3d⁵4s²

Answer: 3d⁵4s²

Question:  The reaction of aqueous KMnO₄ with H₂O₂ in acidic conditions gives

• a) Mn⁴⁺ and O₂  
• b) Mn²⁺ and O₂
• c) Mn²⁺ and O₃ 
• d) Mn⁴⁺ and MnO₂

Answer:  Mn²⁺ and O₂

Question: Which of the following statements about the interstitial compounds is incorrect ?

• a) They are chemically reactive
• b) They are much harder than the pure metal
• c) They have higher melting points than the pure metal
• d) They retain metallic conductivitiy

Answer: They are chemically reactive

Question: In black and white photography, the developed film is fixed by washing with

• a) AgBr solution
• b) Hypo solution
• c) Na₂S₄O₆solution 
• d) FeC₂O₄ solution

Answer: Hypo solution

Question: The metal which can form cation having metal - metal bond

• a) Mercury
• b) Copper
• c) Osmium
• d) Iron

Answer: Mercury

Question: Which one alloy does not contain copper?

• a) Bronze
• b) Brass
• c) German silver
• d) Mischmetal

Answer: Mischmetal

Question: CrO₃ is coloured due to

• a) Crystal defect
• b) Unpaired electrons
• c) Charge transfer spectra
• d) Low I.E.

Answer: Charge transfer spectra

Question:  The element which does not show d⁰ configuration in its highest oxidation state

• a) V
• b) Mn
• c) Cr
• d) Fe

Answer: Fe

Question: Transuranic elements begin with

• a) Np
• b) Cm
• c) Pu
• d) U

Answer: Np

Question: Which oxide of manganese is acidic in nature?

• a) MnO
• b) Mn₂O₇
• c) Mn₂O₃
• d) MnO₂

Answer:  Mn₂O₇

Question: Which of the following is not coloured?

• a) Mn²⁺
• b) Cr³⁺ 
• c) Zn²⁺
• d) Cu²⁺

Answer: Zn²⁺