Unit 9: Classification of Elements and Periodicity in Properties — Online MCQ Test
CHEMISTRY · JEE MAINS · JEE
Practice Unit 9: Classification of Elements and Periodicity in Properties with a free chapter-wise online MCQ test.
This chapter covers: Modern periodic law and present form of the periodic table s p. d and f block elements periodic trendsinproperties of elements atomic and ionic radii ionization enthalpy electron g....
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Unit 9: Classification of Elements and Periodicity in Properties — Important Questions & Answers
Which of the following electronegativity order is incorrect?
- A. F > O > N
- B. C > B > Be
- C. P > S > Cl
- D. N > C > B
Answer: D. N > C > B
Electronegativity increases across a period. The correct order for Period 3 is Cl > S > P. Thus, P > S > Cl is incorrect.
Electronegativity increases across a period. The correct order for Period 3 is Cl > S > P. Thus, P > S > Cl is incorrect.
Which of the following electronegativity order is incorrect?
- A. Mg < Be < B < N
- B. S < Cl < O < F
- C. Al < Si < C < N
- D. Al < Mg < B < N
Answer: D. Al < Mg < B < N
Electronegativity generally increases across a period and decreases down a group. In option (4), Al < Mg is incorrect because Mg (group 2) is to the left of Al (group 13) in the same period; typically, electronegativity increases from left to right (Mg > Al).
Electronegativity generally increases across a period and decreases down a group. In option (4), Al < Mg is incorrect because Mg (group 2) is to the left of Al (group 13) in the same period; typically, electronegativity increases from left to right (Mg > Al).
Match List-I with List-II: (A) Al3+ < Mg2+ < Na+ < F- (I) Ionisation Enthalpy (B) B < C < O < N (II) Metallic character (C) B < Al < Mg < K (III) Electronegativity (D) Si < P < S < Cl (IV) Ionic radii
- A. (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
- B. (A)-(IV), (B)-(I), (C)-(III), (D)-(II)
- C. (A)-(III), (B)-(IV), (C)-(II), (D)-(I)
- D. (A)-(II), (B)-(III), (C)-(IV), (D)-(I)
Answer: A. (A)-(IV), (B)-(I), (C)-(II), (D)-(III)
Matching based on atomic properties: (A) is ionic radii order, (B) ionisation enthalpy (N is higher than O due to stable half-filled), (C) metallic character increases down and left, (D) electronegativity increases across period.
Matching based on atomic properties: (A) is ionic radii order, (B) ionisation enthalpy (N is higher than O due to stable half-filled), (C) metallic character increases down and left, (D) electronegativity increases across period.
Given below are two statements: Statement-I: The correct order in terms of atomic/ionic radii is Al > Mg > Mg2+ > Al3+. Statement-II: The correct order in terms of the magnitude of electron gain enthalpy is Cl > Br > S > O. In the light of the above statements, choose the correct answer:
- A. (1) Both Statement I and Statement II are false
- B. (2) Statement I is false but Statement II is true
- C. (3) Statement I is true but Statement II is false
- D. (4) Both Statement I and Statement II are true
Answer: B. (2) Statement I is false but Statement II is true
Correct order for atomic/ionic radii is Mg > Al > Mg2+ > Al3+. Statement I is false. Statement II is true as Chlorine has the highest electron gain enthalpy.
Correct order for atomic/ionic radii is Mg > Al > Mg2+ > Al3+. Statement I is false. Statement II is true as Chlorine has the highest electron gain enthalpy.
The correct order of metallic character is =
- A. K > Ca > Be
- B. Be > Ca > K
- C. K > Be > Ca
- D. Ca > K > Be
Answer: A. K > Ca > Be
Metallic character increases down a group and decreases across a period. Potassium, an alkali metal, is more metallic than calcium, and calcium is more metallic than beryllium because Be is much higher in the group and smaller in size. Thus the order is $\mathrm{K > Ca > Be}$.
Metallic character increases down a group and decreases across a period. Potassium, an alkali metal, is more metallic than calcium, and calcium is more metallic than beryllium because Be is much higher in the group and smaller in size. Thus the order is $\mathrm{K > Ca > Be}$.