{"id":12760,"date":"2025-09-22T13:50:39","date_gmt":"2025-09-22T12:50:39","guid":{"rendered":"https:\/\/mcqsadda.com\/?p=12760"},"modified":"2025-10-22T10:17:59","modified_gmt":"2025-10-22T09:17:59","slug":"periodic-classification-of-element-top-100-mcqs-with-answer-and-explanation","status":"publish","type":"post","link":"https:\/\/mcqsadda.com\/index.php\/2025\/09\/22\/periodic-classification-of-element-top-100-mcqs-with-answer-and-explanation\/","title":{"rendered":"Periodic classification of element Top 100 MCQs With Answer and Explanation"},"content":{"rendered":"\n

1. Who is known as the father of the modern periodic table?<\/mark><\/strong>
A) Mendeleev
B) Moseley
C) Dobereiner
D) Newlands
Answer:<\/strong> A
Explanation:<\/strong> Dmitri Mendeleev arranged elements based on increasing atomic mass and their properties.<\/p>\n\n\n\n

2. Dobereiner\u2019s law of triads was based on:<\/strong><\/mark>
A) Atomic number
B) Atomic mass
C) Valency
D) Isotopes
Answer:<\/strong> B
Explanation:<\/strong> He grouped elements into triads where the atomic mass of the middle element was approximately the average of the other two.<\/p>\n\n\n\n

3. Newlands\u2019 Law of Octaves stated:<\/mark><\/strong>
A) Every 8th element repeats properties
B) Every 7th element repeats properties
C) Properties depend on valency
D) Elements are arranged in triads
Answer:<\/strong> A
Explanation:<\/strong> Newlands observed periodic repetition of properties after every 8th element.<\/p>\n\n\n\n

4. Limitation of Newlands\u2019 law of octaves:<\/mark><\/strong>
A) Worked only up to calcium
B) Did not consider isotopes
C) Couldn\u2019t explain noble gases
D) All of the above
Answer:<\/strong> D
Explanation:<\/strong> Octaves failed for elements beyond calcium and ignored isotopes\/noble gases.<\/p>\n\n\n\n

5. Mendeleev arranged elements on the basis of:<\/mark><\/strong>
A) Increasing atomic mass
B) Increasing atomic number
C) Atomic size
D) Electronegativity
Answer:<\/strong> A
Explanation:<\/strong> Mendeleev used atomic mass as the basis, later corrected by Moseley.<\/p>\n\n\n\n

6. Mendeleev left gaps in his table for:<\/mark><\/strong>
A) Noble gases
B) Unknown elements
C) Isotopes
D) Transition metals
Answer:<\/strong> B
Explanation:<\/strong> He predicted properties of undiscovered elements like Eka-aluminium (Gallium).<\/p>\n\n\n\n

7. Modern periodic law was given by:<\/mark><\/strong>
A) Mendeleev
B) Moseley
C) Dalton
D) Rutherford
Answer:<\/strong> B
Explanation:<\/strong> Moseley stated that properties of elements depend on atomic number, not atomic mass.<\/p>\n\n\n\n

8. Which law forms the basis of the modern periodic table?<\/mark><\/strong>
A) Law of octaves
B) Mendeleev\u2019s law
C) Modern periodic law
D) Law of constant proportion
Answer:<\/strong> C
Explanation:<\/strong> Moseley\u2019s modern periodic law is the foundation of today\u2019s periodic table.<\/p>\n\n\n\n

9. Noble gases were not included in Mendeleev\u2019s periodic table because:<\/mark><\/strong>
A) They were not discovered
B) They are inert
C) They do not follow octaves
D) Their mass was unknown
Answer:<\/strong> A
Explanation:<\/strong> Noble gases were discovered later (1894 onwards).<\/p>\n\n\n\n

10. Eka-silicon predicted by Mendeleev was later discovered as:<\/mark><\/strong>
A) Germanium
B) Gallium
C) Silicon
D) Tin
Answer:<\/strong> A
Explanation:<\/strong> Eka-silicon was Germanium (Ge).<\/p>\n\n\n\n

11. Eka-aluminium predicted by Mendeleev was:<\/mark><\/strong>
A) Indium
B) Gallium
C) Thallium
D) Aluminium
Answer:<\/strong> B
Explanation:<\/strong> Eka-aluminium turned out to be Gallium.<\/p>\n\n\n\n

12. The limitation of Mendeleev\u2019s periodic table was:<\/mark><\/strong>
A) Position of isotopes
B) Position of hydrogen
C) Anomalous mass order
D) All of the above
Answer:<\/strong> D
Explanation:<\/strong> Isotopes and hydrogen could not be placed properly.<\/p>\n\n\n\n

13. Who discovered the atomic number?<\/mark><\/strong>
A) Moseley
B) Bohr
C) Mendeleev
D) Dalton
Answer:<\/strong> A
Explanation:<\/strong> Henry Moseley discovered atomic number using X-ray spectra.<\/p>\n\n\n\n

14. How many elements were known at the time of Mendeleev?<\/mark><\/strong>
A) 56
B) 63
C) 72
D) 92
Answer:<\/strong> B
Explanation:<\/strong> Mendeleev worked with 63 known elements.<\/p>\n\n\n\n

15. Modern periodic law states that:<\/mark><\/strong>
A) Properties depend on atomic mass
B) Properties depend on atomic number
C) Properties depend on valency
D) Properties depend on isotopes
Answer:<\/strong> B
Explanation:<\/strong> Atomic number determines properties, not mass.<\/p>\n\n\n\n

16. Which element challenged Mendeleev\u2019s arrangement?<\/strong><\/mark>
A) Argon & Potassium
B) Cobalt & Nickel
C) Tellurium & Iodine
D) All of the above
Answer:<\/strong> D
Explanation:<\/strong> Mass order and properties conflicted in these cases.<\/p>\n\n\n\n

17. The modern periodic table was first prepared by:<\/mark><\/strong>
A) Mendeleev
B) Moseley
C) Bohr
D) Seaborg
Answer:<\/strong> C
Explanation:<\/strong> Bohr prepared a long form of the periodic table.<\/p>\n\n\n\n

18. Noble gases were discovered by:<\/mark><\/strong>
A) William Ramsay
B) Moseley
C) Mendeleev
D) Bohr
Answer:<\/strong> A
Explanation:<\/strong> Ramsay discovered noble gases (1894 onwards).<\/p>\n\n\n\n

19. Which element was not discovered during Mendeleev\u2019s time?<\/mark><\/strong>
A) Gallium
B) Argon
C) Germanium
D) Scandium
Answer:<\/strong> B
Explanation:<\/strong> Argon was discovered later in 1894.<\/p>\n\n\n\n

20. Triads concept was proposed by:<\/mark><\/strong>
A) Dobereiner
B) Newlands
C) Mendeleev
D) Moseley
Answer:<\/strong> A
Explanation:<\/strong> Dobereiner\u2019s triads grouped elements in threes.<\/p>\n\n\n\n


21. Which element does not fit into Dobereiner\u2019s triads?<\/mark><\/strong>
A) Cl, Br, I
B) Li, Na, K
C) Ca, Sr, Ba
D) H, He, Li
Answer:<\/strong> D
Explanation:<\/strong> H, He, Li do not follow the triad rule.<\/p>\n\n\n\n

22. Newlands\u2019 law of octaves failed because:<\/mark><\/strong>
A) He placed two elements in one slot
B) Did not leave space for undiscovered elements
C) Worked only up to calcium
D) All of the above
Answer:<\/strong> D
Explanation:<\/strong> These were major drawbacks.<\/p>\n\n\n\n

23. Which property did Mendeleev not consider while arranging elements?<\/mark><\/strong>
A) Oxides
B) Hydrides
C) Atomic number
D) Atomic mass
Answer:<\/strong> C
Explanation:<\/strong> Atomic number was not discovered then.<\/p>\n\n\n\n

24. Which two elements were placed together despite different atomic masses by Mendeleev?<\/mark><\/strong>
A) Co and Ni
B) Ar and K
C) Te and I
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Such anomalies occurred in his table.<\/p>\n\n\n\n

25. The long form of the periodic table is also called:<\/mark><\/strong>
A) Mendeleev\u2019s table
B) Bohr\u2019s table
C) Modern periodic table
D) Octave table
Answer:<\/strong> C
Explanation:<\/strong> The long form (modern) periodic table is widely used today.<\/p>\n\n\n\n

26. The modern periodic table is based on:<\/mark><\/strong>
A) Atomic mass
B) Atomic number
C) Valency
D) Isotopes
Answer:<\/strong> B
Explanation:<\/strong> Moseley showed that atomic number determines properties of elements.<\/p>\n\n\n\n

27. How many periods are there in the modern periodic table?<\/mark><\/strong>
A) 7
B) 8
C) 9
D) 6
Answer:<\/strong> A
Explanation:<\/strong> The periodic table has 7 horizontal periods.<\/p>\n\n\n\n

28. How many groups are present in the modern periodic table?<\/mark><\/strong>
A) 7
B) 8
C) 18
D) 9
Answer:<\/strong> C
Explanation:<\/strong> The modern periodic table consists of 18 vertical groups.<\/p>\n\n\n\n

29. The elements of group 18 are called:<\/mark><\/strong>
A) Halogens
B) Alkali metals
C) Noble gases
D) Transition elements
Answer:<\/strong> C
Explanation:<\/strong> Group 18 elements are noble gases with stable electronic configurations.<\/p>\n\n\n\n

30. The elements of group 17 are known as:<\/mark><\/strong>
A) Chalcogens
B) Halogens
C) Noble gases
D) Alkali metals
Answer:<\/strong> B
Explanation:<\/strong> Group 17 elements (F, Cl, Br, I, At) are halogens.<\/p>\n\n\n\n

31. The elements of group 1 are:<\/mark><\/strong>
A) Alkali metals
B) Alkaline earth metals
C) Transition metals
D) Noble gases
Answer:<\/strong> A
Explanation:<\/strong> Group 1 elements (Li, Na, K, etc.) are called alkali metals.<\/p>\n\n\n\n

32. Group 2 elements are called:<\/mark><\/strong>
A) Alkali metals
B) Alkaline earth metals
C) Halogens
D) Noble gases
Answer:<\/strong> B
Explanation:<\/strong> Group 2 elements (Be, Mg, Ca, etc.) are alkaline earth metals.<\/p>\n\n\n\n

33. Which period contains the maximum number of elements?<\/mark><\/strong>
A) 1st
B) 2nd
C) 6th
D) 7th
Answer:<\/strong> C
Explanation:<\/strong> The 6th period has 32 elements including lanthanides.<\/p>\n\n\n\n

34. Which of the following elements belongs to group 16?<\/mark><\/strong>
A) Nitrogen
B) Oxygen
C) Chlorine
D) Sodium
Answer:<\/strong> B
Explanation:<\/strong> Oxygen family (O, S, Se, Te, Po) are group 16 elements (chalcogens).<\/p>\n\n\n\n

35. Which is the first element of the modern periodic table?<\/mark><\/strong>
A) Hydrogen
B) Helium
C) Lithium
D) Beryllium
Answer:<\/strong> A
Explanation:<\/strong> Hydrogen (Z = 1) is the first element.<\/p>\n\n\n\n

36. Which is the last naturally occurring element in the periodic table?<\/mark><\/strong>
A) Uranium
B) Thorium
C) Plutonium
D) Fermium
Answer:<\/strong> A
Explanation:<\/strong> Uranium (Z = 92) is the last naturally occurring element.<\/p>\n\n\n\n

37. Which element has the highest electronegativity?<\/mark><\/strong>
A) Oxygen
B) Fluorine
C) Chlorine
D) Nitrogen
Answer:<\/strong> B
Explanation:<\/strong> Fluorine (EN = 3.98) is the most electronegative element.<\/p>\n\n\n\n

38. In a period, atomic size generally:<\/mark><\/strong>
A) Increases from left to right
B) Decreases from left to right
C) Remains constant
D) Increases and then decreases
Answer:<\/strong> B
Explanation:<\/strong> Across a period, nuclear charge increases, pulling electrons closer.<\/p>\n\n\n\n

39. In a group, atomic size generally:<\/mark><\/strong>
A) Increases down the group
B) Decreases down the group
C) Remains constant
D) First decreases then increases
Answer:<\/strong> A
Explanation:<\/strong> New shells are added down the group, increasing atomic radius.<\/p>\n\n\n\n

40. Ionization energy across a period generally:<\/mark><\/strong>
A) Decreases
B) Increases
C) Remains constant
D) Random
Answer:<\/strong> B
Explanation:<\/strong> More nuclear charge across a period increases ionization energy.<\/p>\n\n\n\n

41. Ionization energy down a group:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Increases irregularly
Answer:<\/strong> B
Explanation:<\/strong> Larger atomic size and shielding effect lower ionization energy.<\/p>\n\n\n\n

42. Electron affinity across a period generally:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> A
Explanation:<\/strong> Smaller size and higher nuclear charge increase electron affinity across a period.<\/p>\n\n\n\n

43. Electron affinity down a group:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> B
Explanation:<\/strong> Larger size reduces effective attraction for extra electrons.<\/p>\n\n\n\n

44. Metallic character across a period:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> B
Explanation:<\/strong> Across a period, tendency to lose electrons decreases \u2192 less metallic.<\/p>\n\n\n\n

45. Metallic character down a group:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> A
Explanation:<\/strong> Down a group, larger atoms lose electrons easily \u2192 more metallic.<\/p>\n\n\n\n

46. Non-metallic character across a period:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> A
Explanation:<\/strong> Across a period, tendency to gain electrons increases.<\/p>\n\n\n\n

47. Which group is also called \u201calkali metals\u201d?<\/mark><\/strong>
A) Group 2
B) Group 1
C) Group 13
D) Group 18
Answer:<\/strong> B
Explanation:<\/strong> Group 1 metals (Li, Na, K) form strong alkalis with water.<\/p>\n\n\n\n

48. The most metallic element is:<\/mark><\/strong>
A) Cesium
B) Sodium
C) Francium
D) Potassium
Answer:<\/strong> C
Explanation:<\/strong> Francium is the most metallic (least electronegative, lowest ionization energy).<\/p>\n\n\n\n

49. The most non-metallic element is:<\/mark><\/strong>
A) Fluorine
B) Oxygen
C) Chlorine
D) Nitrogen
Answer:<\/strong> A
Explanation:<\/strong> Fluorine has highest non-metallic nature due to high electronegativity.<\/p>\n\n\n\n

50. Which element has the smallest atomic radius?<\/mark><\/strong>
A) Hydrogen
B) Helium
C) Lithium
D) Fluorine
Answer:<\/strong> B
Explanation:<\/strong> Helium has the smallest atomic size because of its high nuclear charge and no shielding.<\/p>\n\n\n\n

51. First ionization energy is defined as:<\/mark><\/strong>
A) Energy required to remove an electron from a cation
B) Energy released when an electron is added to an atom
C) Energy required to remove one electron from a neutral atom
D) Energy required to remove a proton
Answer:<\/strong> C
Explanation:<\/strong> First ionization energy (IE\u2081) is the energy needed to remove one electron from a neutral gaseous atom.<\/p>\n\n\n\n

52. Second ionization energy is:<\/mark><\/strong>
A) Always smaller than the first
B) Equal to the first
C) Always greater than the first
D) None of these
Answer:<\/strong> C
Explanation:<\/strong> Removing a second electron is harder due to increased effective nuclear charge.<\/p>\n\n\n\n

53. Across a period, ionization energy:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> A
Explanation:<\/strong> Nuclear charge increases \u2192 electrons are held tightly \u2192 higher IE.<\/p>\n\n\n\n

54. Down a group, ionization energy:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Varies randomly
Answer:<\/strong> B
Explanation:<\/strong> Electrons are farther from nucleus and shielding increases \u2192 IE decreases.<\/p>\n\n\n\n

55. Electronegativity of an element:<\/mark><\/strong>
A) Tendency to donate electrons
B) Tendency to attract bonding electrons
C) Tendency to lose protons
D) None of these
Answer:<\/strong> B
Explanation:<\/strong> Electronegativity measures how strongly an atom attracts shared electrons in a bond.<\/p>\n\n\n\n

56. Electronegativity across a period:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> A
Explanation:<\/strong> Nuclear charge increases, atomic size decreases \u2192 stronger attraction for electrons.<\/p>\n\n\n\n

57. Electronegativity down a group:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> B
Explanation:<\/strong> Larger atoms \u2192 bonding electrons are farther from nucleus \u2192 lower electronegativity.<\/p>\n\n\n\n

58. Atomic size across a period:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> B
Explanation:<\/strong> Nuclear charge increases \u2192 electrons pulled closer \u2192 smaller size.<\/p>\n\n\n\n

59. Atomic size down a group:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> A
Explanation:<\/strong> Extra electron shells increase the size despite nuclear charge.<\/p>\n\n\n\n

60. Cation size is:<\/mark><\/strong>
A) Larger than neutral atom
B) Smaller than neutral atom
C) Same as neutral atom
D) Random
Answer:<\/strong> B
Explanation:<\/strong> Cations have fewer electrons \u2192 smaller radius due to less electron\u2013electron repulsion.<\/p>\n\n\n\n

61. Anion size is:<\/mark><\/strong>
A) Larger than neutral atom
B) Smaller than neutral atom
C) Same as neutral atom
D) Random
Answer:<\/strong> A
Explanation:<\/strong> Extra electrons increase repulsion \u2192 larger radius.<\/p>\n\n\n\n

62. Metallic character across a period:<\/mark><\/strong>
A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> B
Explanation:<\/strong> Tendency to lose electrons decreases \u2192 less metallic.<\/p>\n\n\n\n

63. Metallic character down a group:<\/mark>
<\/strong>A) Increases
B) Decreases
C) Remains constant
D) Random
Answer:<\/strong> A
Explanation:<\/strong> Larger atoms lose electrons easily \u2192 more metallic.<\/p>\n\n\n\n

64. Which type of oxides are formed by metals?<\/mark><\/strong>
A) Acidic
B) Basic
C) Amphoteric
D) Neutral
Answer:<\/strong> B
Explanation:<\/strong> Metals react with oxygen to form basic oxides (e.g., Na\u2082O, CaO).<\/p>\n\n\n\n

65. Which type of oxides are formed by non-metals?<\/mark><\/strong>
A) Acidic
B) Basic
C) Amphoteric
D) Neutral
Answer:<\/strong> A
Explanation:<\/strong> Non-metals form acidic oxides (e.g., CO\u2082, SO\u2082).<\/p>\n\n\n\n

66. Amphoteric oxides show:<\/mark><\/strong>
A) Acidic behavior only
B) Basic behavior only
C) Both acidic and basic behavior
D) None
Answer:<\/strong> C
Explanation:<\/strong> Oxides like Al\u2082O\u2083 and ZnO react with both acids and bases.<\/p>\n\n\n\n

67. Oxides of elements in period 3 show:<\/mark><\/strong>
A) All basic
B) All acidic
C) Basic \u2192 Amphoteric \u2192 Acidic trend
D) Random
Answer:<\/strong> C
Explanation:<\/strong> Na\u2082O, MgO \u2192 basic; Al\u2082O\u2083 \u2192 amphoteric; SiO\u2082, P\u2084O\u2081\u2080 \u2192 acidic.<\/p>\n\n\n\n

68. Oxides of halogens are:<\/mark><\/strong>
A) Basic
B) Acidic
C) Amphoteric
D) Neutral
Answer:<\/strong> B
Explanation:<\/strong> Non-metal halogen oxides (Cl\u2082O, Cl\u2082O\u2087) are acidic.<\/p>\n\n\n\n

69. Ionization energy of noble gases is:<\/mark><\/strong>
A) Very low
B) Very high
C) Moderate
D) Variable
Answer:<\/strong> B
Explanation:<\/strong> Noble gases have full valence shells \u2192 very stable \u2192 high IE.<\/p>\n\n\n\n

70. Fluorine is most reactive because:<\/mark><\/strong>
A) Small size & high electronegativity
B) Large size
C) Low ionization energy
D) None
Answer:<\/strong> A
Explanation:<\/strong> High electronegativity and small radius \u2192 reacts vigorously.<\/p>\n\n\n\n

71. Alkali metals are highly reactive because:<\/mark><\/strong>
A) High electronegativity
B) Low ionization energy
C) Small size
D) High electron affinity
Answer:<\/strong> B
Explanation:<\/strong> Easily lose outer electron \u2192 high reactivity.<\/p>\n\n\n\n

72. Most electronegative element in period 2 is:<\/mark><\/strong>
A) Li
B) C
C) O
D) F
Answer:<\/strong> D
Explanation:<\/strong> Fluorine has the highest electronegativity (3.98).<\/p>\n\n\n\n

73. Hydrogen is placed in group 1 because:<\/mark><\/strong>
A) It has 1 electron in valence shell
B) It forms cations
C) It behaves like alkali metal in reactions
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Hydrogen shares properties of group 1 (valence e\u207b, cation formation).<\/p>\n\n\n\n

74. Hydrogen is placed in group 17 in some tables because:<\/mark><\/strong>
A) It forms H\u207b ions
B) It behaves like halogen
C) Both A & B
D) None
Answer:<\/strong> C
Explanation:<\/strong> Hydrogen can gain one electron \u2192 forms hydride (H\u207b), similar to halogens.<\/p>\n\n\n\n

75. Most acidic oxide among period 3 elements is:<\/mark><\/strong>
A) Na\u2082O
B) MgO
C) SiO\u2082
D) P\u2084O\u2081\u2080
Answer:<\/strong> D
Explanation:<\/strong> P\u2084O\u2081\u2080 is strongly acidic \u2192 reacts with water to form H\u2083PO\u2084.<\/p>\n\n\n\n

76. Transition elements are characterized by:<\/mark><\/strong>
A) Partially filled d-orbitals
B) Partially filled p-orbitals
C) Completely filled s-orbitals only
D) Fully filled d-orbitals
Answer:<\/strong> A
Explanation:<\/strong> Transition metals have incomplete d-orbitals in their ground or common oxidation state.<\/p>\n\n\n\n

77. Which of the following is a transition metal?
<\/mark><\/strong>A) Scandium (Sc)
B) Sodium (Na)
C) Magnesium (Mg)
D) Calcium (Ca)
Answer:<\/strong> A
Explanation:<\/strong> Scandium has partially filled d-orbitals \u2192 transition element.<\/p>\n\n\n\n

78. Which of the following is not a transition element?<\/mark><\/strong>
A) Zinc (Zn)
B) Iron (Fe)
C) Copper (Cu)
D) Titanium (Ti)
Answer:<\/strong> A
Explanation:<\/strong> Zn has fully filled 3d\u00b9\u2070 orbitals \u2192 not a true transition element.<\/p>\n\n\n\n

79. Common oxidation states of transition metals are:<\/mark><\/strong>
A) Only +1
B) +2 and +3 (variable)
C) Only +2
D) Only +3
Answer:<\/strong> B
Explanation:<\/strong> Transition metals exhibit variable oxidation states due to involvement of (n\u20131)d and ns electrons.<\/p>\n\n\n\n

80. Which of the following elements shows +6 oxidation state?<\/mark><\/strong>
A) Chromium
B) Iron
C) Copper
D) Zinc
Answer:<\/strong> A
Explanation:<\/strong> Chromium forms CrO\u2083 \u2192 oxidation state +6.<\/p>\n\n\n\n

81. Which transition element forms colored compounds?<\/mark><\/strong>
A) Titanium
B) Vanadium
C) Copper
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Partially filled d-orbitals \u2192 d\u2013d transitions \u2192 colored compounds.<\/p>\n\n\n\n

82. Transition elements often exhibit:<\/mark><\/strong>
A) Magnetic properties
B) Catalytic behavior
C) Formation of complex compounds
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Variable oxidation states and unpaired electrons enable these properties.<\/p>\n\n\n\n

83. Lanthanides are also called:<\/mark><\/strong>
A) Rare earth elements
B) Noble gases
C) Alkali metals
D) Actinides
Answer:<\/strong> A
Explanation:<\/strong> Lanthanides (Ce\u2013Lu) are known as rare earth elements.<\/p>\n\n\n\n

84. The general electronic configuration of lanthanides is:<\/mark><\/strong>
A) [Xe] 4f\u207f5d\u20706s\u00b2
B) [Xe] 5d\u207f6s\u00b2
C) [Xe] 4d\u207f5s\u00b2
D) [Xe] 3d\u207f4s\u00b2
Answer:<\/strong> A
Explanation:<\/strong> Lanthanides fill 4f orbitals (4f\u207f5d\u20706s\u00b2).<\/p>\n\n\n\n

85. Actinides are characterized by:<\/mark><\/strong>
A) Filling 5f orbitals
B) Filling 4f orbitals
C) Filling 3d orbitals
D) Filling 6d orbitals
Answer:<\/strong> A
Explanation:<\/strong> Actinides (Th\u2013Lr) have filling of 5f orbitals.<\/p>\n\n\n\n

86. Which actinide is used as fuel in nuclear reactors?<\/mark><\/strong>
A) Uranium
B) Thorium
C) Plutonium
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> U, Th, and Pu isotopes are used as nuclear fuel.<\/p>\n\n\n\n

87. Transition metals act as good catalysts because:<\/mark><\/strong>
A) They are colored
B) They have variable oxidation states
C) They are hard metals
D) They are dense
Answer:<\/strong> B
Explanation:<\/strong> Variable oxidation states allow them to facilitate reactions without being consumed.<\/p>\n\n\n\n

88. Most stable oxidation state of Zn is:<\/mark><\/strong>
A) +1
B) +2
C) +3
D) 0
Answer:<\/strong> B
Explanation:<\/strong> Zn forms only +2 because d-orbitals are completely filled.<\/p>\n\n\n\n

89. Elements showing f-block contraction:<\/mark><\/strong>
A) Lanthanides
B) Actinides
C) Both A & B
D) Transition elements
Answer:<\/strong> C
Explanation:<\/strong> Poor shielding by f-electrons \u2192 contraction in size across series.<\/p>\n\n\n\n

90. The common oxidation state of cerium (Ce) is:<\/mark><\/strong>
A) +2
B) +3
C) +4
D) +6
Answer:<\/strong> C
Explanation:<\/strong> Ce exhibits both +3 and +4 states; +4 is common in CeO\u2082.<\/p>\n\n\n\n

91. Transition metals form colored ions due to:<\/mark><\/strong>
A) f\u2013f transitions
B) d\u2013d transitions
C) s\u2013s transitions
D) p\u2013p transitions
Answer:<\/strong> B
Explanation:<\/strong> Partially filled d-orbitals allow electronic transitions \u2192 color.<\/p>\n\n\n\n

92. Which element is used in making blue pigment?<\/mark><\/strong>
A) Copper
B) Cobalt
C) Nickel
D) Titanium
Answer:<\/strong> B
Explanation:<\/strong> Cobalt compounds (Co\u00b2\u207a) give blue color in glass and ceramics.<\/p>\n\n\n\n

93. Which property is enhanced due to transition metals\u2019 unpaired electrons?<\/mark><\/strong>
A) Paramagnetism
B) Density
C) Atomic radius
D) Ionization energy
Answer:<\/strong> A
Explanation:<\/strong> Unpaired d-electrons lead to paramagnetic behavior.<\/p>\n\n\n\n

94. Oxides of transition elements are generally:<\/mark><\/strong>
A) Basic
B) Amphoteric
C) Acidic
D) Neutral
Answer:<\/strong> B
Explanation:<\/strong> Many oxides (ZnO, Al\u2082O\u2083, Cr\u2082O\u2083) react with both acids and bases.<\/p>\n\n\n\n

95. Most stable oxidation state of manganese is:<\/mark><\/strong>
A) +2
B) +4
C) +7
D) +3
Answer:<\/strong> A
Explanation:<\/strong> Mn\u00b2\u207a (d\u2075) is stable due to half-filled d-orbital stability.<\/p>\n\n\n\n

96. Which lanthanide is used in making strong permanent magnets?<\/mark><\/strong>
A) Neodymium
B) Cerium
C) Samarium
D) Europium
Answer:<\/strong> A
Explanation:<\/strong> Nd\u2082Fe\u2081\u2084B magnets are very strong due to Nd\u00b3\u207a ions.<\/p>\n\n\n\n

97. Which actinide is used in nuclear weapons?<\/mark><\/strong>
A) Uranium-235
B) Thorium
C) Neptunium
D) Plutonium-239
Answer:<\/strong> D
Explanation:<\/strong> Plutonium-239 is fissile \u2192 used in nuclear weapons.<\/p>\n\n\n\n

98.<\/mark><\/strong> Which element shows variable oxidation states from +2 to +7?
<\/mark><\/strong>A) Chromium
B) Iron
C) Copper
D) Zinc
Answer:<\/strong> A
Explanation:<\/strong> Cr forms Cr\u00b2\u207a, Cr\u00b3\u207a, Cr\u2076\u207a, etc.<\/p>\n\n\n\n

99. Transition metals are less reactive than alkali metals because:<\/mark><\/strong>
A) They have higher ionization energy
B) They have variable oxidation states
C) They have d-electrons
D) All of these
Answer:<\/strong> D
Explanation:<\/strong> Higher IE and d-electrons reduce their tendency to lose electrons rapidly.<\/p>\n\n\n\n

100. The most important application of transition metals is:<\/mark><\/strong>
A) Industrial catalysis
B) Jewelry
C) Nuclear fuel
D) Household cleaning
Answer:<\/strong> A
Explanation:<\/strong> Transition metals (Fe, Pt, Ni, etc.) are widely used as catalysts in industry.<\/p>\n","protected":false},"excerpt":{"rendered":"

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