CBSE Class 12 Chemistry The d and f Block Elements MCQs Set A

Question : Malachite is an ore of 

(a) Silver        
(b) Mercury
(c) Magnesium
(d) Copper

Answer : D

Question : The chief ore of Hg is

(a) Pyrolusite
(b) Bauxite
(c) Galena     
(d) Cinnabar

Answer : D

Question : The transition element which shows the highest oxidation state is: 

(a) Iron           
(b) Vanadium
(c) Manganese
(d) Chromium

Answer : C

Question : Gun metal is

(a) Cu + Zn
(b) Cu + Sn + Zn
(c) Cu + Sn 
(d) Zn + Sn

Answer : B

Question : Transition elements form coloured ions due to : 

(a) d-d transition
(b) fully filled d-orbitals
(c) smaller atomic radii
(d) availability of s-electrons

Answer : A

Question : CuSO₄ and KCN react to produce

(a) CuCN₂           
(b) CuCN
(c) K₃[Cu(CN)₄]  
(d) K₄[Cu(CN)₆ ]

Answer : C

Question : Which of the following is greatest paramagnetic?

(a) Cu⁺    
(b) Fe²⁺
(c) Fe³⁺   
(d) Cu²⁺

Answer : C

Question : German silver is an alloy of:

(a) Fe, Cr, Ni 
(b) Ag, Cu Au
(c) Cu, Zn, Ni
(d) Cu, Zn, Sn

Answer : C

Question : The composition of duralumin is

(a) Al 94%, Mg 6%
(b) Cu 56%, Zn 24%, Ni 20%
(c) Cu 95%, Al 5%
(d) Al 95%, Cu 4%, Mn 0.5%, Mg 0.5%

Answer : D

Question : The number of water molecules in Mohr's salt is

(a) 2
(b) 4
(c) 6
(d) 8

Answer : C

Question : Philosopher's wool on heating with BaO at 1100°C produces

(a) Ba + ZnCl₂
(b) BaCdO₂
(c) BaZnO₂     
(d) BaO₂ + Zn

Answer : C

Question : Which of the following is not an ore of iron?

(a) limonite   
(b) casiterite
(c) magnetite
(d) none of these

Answer : B

Question : Lanthanide for which +II and +III oxidation states are common is

(a) La
(b) Pr
(c) Ce
(d) Eu

Answer : D

Question : F₂ is formed by reacting K₂MnF₆ with
(a) SbF₅   
(b) MnF₃
(c) KSbF₆ 
(d) MnF₄

Answer : A

Question : The colour imparted by Co(Il) compounds to glass is:

(a) Green
(b) Deep blue
(c) Yellow
(d) Red

Answer : B

Question : Which of the following radioisotopes is used as anticancerous?

(a) Na-24
(b) C-14
(c) U-235
(d) Co-60

Answer : D

Question : Which of the following compound is coloured?

(a) TiCl₃    
(b) FeCl₃
(c) CoCl₂  
(d) All of these

Answer : D

Question : To obtain silver from silver amalgam, it is heated in vessel which is made of

(a) Cu 
(b) Fe
(c) Ni  
(d) Zn

Answer : B

Question : The colour of copper sulphide is

(a) Blue
(b) Black
(c) Red
(d) Green

Answer : B

Question : Which one of the following statements concerning lanthanide elements is false?

(a) Lanthanides are separated from one another by ion exchange method
(b) The ionic radii of trivalent lanthanides steadily increase with increase in atomic number
(c) All lanthanides are highly dense metals
(d) Most characteristic oxidation state of lanthanides is +3

Answer : B 

Question : What is wrong about transition metals?
(a) Diamagnetic
(b) Paramagnetic
(c) Form complexes
(d) Shows variable oxidation state

Answer : A

Question : Correct electronic configuration of Cr (Z = 24) is
(a) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d ⁷ 4s¹
(b) 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹
(c) 1s² 2s² 2p⁶ 3s2 3p6 3d 7 4s²
(d) 1s² 2s² 2p⁶ 3s² 3p6 3d 6 4s²

Answer : B

Question : Which of the following configuration is correct for iron ?
(a) 1s²,2s² 2p⁶,3s²3p⁶3d4
(b) 1s²,2s²2p⁶,3s²3p⁶3d⁶4s²
(c) 1s²,2s²2p6,3s²3p⁶3d2
(d) 1s²,2s²2p6,3s²3p⁶3d24s²

Answer : B

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

(a) Ni³⁺
(b) Mn³⁺
(c) Fe³⁺
(d) Co³⁺

(At. Nos. Mn = 25, Fe = 26, Co = 27, Ni = 28)

Answer : D

Question : Which of the following element does not belong to first transition series?

(a) Fe 

(b) V

(c) Ag 

(d) Cu

Answer : C

Question : (n-1)d¹⁰ns² is the general electronic configuration of

(a) Fe, Co, Ni 

(b) Cu, Ag, Au

(c) Zn, Cd, Hg 

(d) Se, Y, La

Answer : C

Question : The last electron in d-block elements goes to

(a) (n-1) d 

(b) nd

(c) np (d) 

(n-1) s

Answer : A

Question : The elements which exhibit both vertical and horizontal similarites are

(a) inert gas elements 

(b) representative elements

(c) rare elements 

(d) transition elements

Answer : D

Question : An atom has electronic configuration 1s² 2s² 2p⁶3s²3p⁶3d³4s² in which group would it be placed?

(a) Fifth 

(b) Fifteenth

(c) Second 

(d) Third

Answer : A

Question : In 3d-series atomic number (Z) varies from

(a) Z = 21- 30 

(b) Z = 22 - 30

(c) Z = 20 - 30 

(d) Z = 31- 40

Answer : A

Question : The valence shell of transition elements consists of

(a) nd orbitals 

(b) (n-1) d orbitals

(c) ns np nd orbitals 

(d) (n-1) d ns orbitals

Answer : D

Question : Number of unpaired electrons in Ni²⁺(Z=28) is

(a) 4 

(b) 2

(c) 6 

(d) 8

Answer : B

Question : Which of the following element is not a member of transition elements ?

(a) Zn 

(b) Pt

(c) Ce 

(d) Mo

Answer : C

Question : The number of unpaired electrons in gaseous species of Mn³⁺, Cr³⁺ and V³⁺ respectively are.

(a) 4, 3 and 2 

(b) 3, 3 and 2

(c) 4, 3 and 2 

(d) 3, 3 and 3

Answer : C

Question : The first element in the 3d-transition series is

(a) Sc 

(b) Ti

(c) V 

(d) Ca

Answer : A

Question : Which of the following has more unpaired d-electrons?

(a) Zn⁺ 

(b) Fe²⁺

(c) Ni⁺ 

(d) Cu⁺

Answer : B