CBSE Class 11 Chemistry VBQs Classification Of Elements And Periodicity

Question. Identify the incorrect match.
Name IUPAC         Official Name
(A) Unnilunium      (i) Mendelevium
(B) Unniltrium       (ii) Lawrencium
(C) Unnilhexium    (iii) Seaborgium
(D) Unununnium   (iv) Darmstadtium
(a) (A), (i)
(b) (B), (ii)
(c) (C), (iii)
(d) (D), (iv)
Answer. D

Question. The element Z = 114 has been discovered recently. It will belong to which of the following family/group and electronic configuration?
(a) Carbon family, [Rn] 5f¹⁴6d¹⁰ 7s² 7p²
(b) Oxygen family, [Rn] 5f ¹⁴ 6d¹⁰ 7s² 7p⁴
(c) Nitrogen family, [Rn] 5f ¹⁴ 6d¹⁰ 7s² 7p⁶
(d) Halogen family, [Rn] 5f ¹⁴ 6d¹⁰ 7s² 7p⁵
Answer. A

Question. An atom has electronic configuration 1s² 2s² 2p⁶ 3s²  3p⁶ 3d³ 4s² , you will place it in
(a) fifth group
(b) fifteenth group
(c) second group
(d) third group. 
Answer. A

Question. The electronic configuration of an element is 1s²2s²2p⁶ 3s² 3p³. What is the atomic number of the element, which is just below the above element in the periodic table?
(a) 36 
b) 49
(c) 33
(d) 34 
Answer. C

Question. If the atomic number of an element is 33, it will be placed in the periodic table in the
(a) first group
(b) third group
(c) fifth group
(d) seventh group. 
Answer. C

Question. The electronic configuration of four elements are given below. Which elements does not belong to the same family as others?
(a) [Xe]4f¹⁴5d¹⁰4s²
(b) [Kr]4d¹⁰5s²
(c) [Ne]3s²3p⁵
(d) [Ar]3d¹⁰4s² 
Answer. C

Question. For the second period elements the correct increasing order of first ionization enthalpy is
(a) Li < Be < B < C < O < N < F < Ne
(b) Li < Be < B < C < N < O < F < Ne
(c) Li < B < Be < C < O < N < F < Ne
(d) Li < B < Be < C < N < O < F < Ne 
Answer. C

Question. Match the oxide given in column I with its property given in column II.
Column I             Column II
(i) Na₂O              A. Neutral
(ii) Al₂O₃             B. Basic
(iii) N₂O              C. Acidic
(iv) Cl₂O₇           D. Amphoteric
Which of the following options has all correct pairs?
(a) (i)-B, (ii)-A, (iii)-D, (iv)-C
(b) (i)-C, (ii)-B, (iii)-A, (iv)-D
(c) (i)-A, (ii)-D, (iii)-B, (iv)-C
(d) (i)-B, (ii)-D, (iii)-A, (iv)-C 
Answer. D

Question. Which of the following oxides is most acidic in nature?
(a) MgO
(b) BeO
(c) BaO
(d) CaO 
Answer. B

Question. In which of the following options the order of arrangement does not agree with the variation of property indicated against it?
(a) I < Br < Cl < F (increasing electron gain enthalpy)
(b) Li < Na < K < Rb (increasing metallic radius)
(c) Al³⁺< Mg²⁺< Na⁺ < F^– (increasing ionic size)
(d) B < C < N < O (increasing first ionisation enthalpy)
Answer.  A,D

Question. Which of the following orders of ionic radii is correctly represented?
(a) H^–> H⁺> H
(b) Na⁺ > F^– > O^2–
(c) F^– > O^2– > Na⁺
(d) Al³⁺ > Mg²⁺ > N^3–
Answer. None

Question. Which one of the following arrangements represents the correct order of least negative to most negative electron gain enthalpy for C, Ca, Al, F and O?
(a) Al < Ca < O < C < F
(b) Al < O < C < Ca < F
(c) C < F < O < Al < Ca
(d) Ca < Al < C < O < F 
Answer. D

Question. In which of the following arrangements the given sequence is not strictly according to the property indicated against it?
(a) HF < HCl < HBr < HI : increasing acidic strength
(b) H₂O < H₂S < H₂Se < H₂Te : increasing pKa values
(c) NH₃< PH₃< AsH₃ < SbH₃ : increasing acidic character
(d) CO₂ < SiO₂ < SnO₂ < PbO₂ : increasing oxidising power 
Answer. B

Question. Identify the wrong statement in the following.
(a) Amongst isoelectronic species, smaller the positive charge on the cation, smaller is the ionic radius.
(b) Amongst isoelectronic species, greater the negative charge on the anion, larger is the ionic radius.
(c) Atomic radius of the elements increases as one moves down the first group of the periodic table.
(d) Atomic radius of the elements decreases as one moves across from left to right in the 2nd period of the periodic table.
Answer. A

Question. What is the value of electron gain enthalpy of Na+ if IE₁of Na = 5.1 eV?
(a) –5.1 eV
(b) –10.2 eV
(c) +2.55 eV
(d) +10.2 eV 
Answer. A

Question. Which of the following oxides is amphoteric?
(a) SnO₂
(b) CaO
(c) SiO₂
(d) CO₂
Answer. A

Question. The correct order of the decreasing ionic radii among the following isoelectronic species is
(a) Ca²⁺> K⁺> S^2– > Cl^–
(b) Cl^– > S^2– > Ca²⁺ > K⁺
(c) S^2– > Cl^– > K⁺ > Ca²⁺
(d) K⁺ > Ca²⁺ > Cl^– > S^2–
Answer. C

Question. Which of the following represents the correct order of increasing electron gain enthalpy with negative sign for the elements O, S, F and Cl?
(a) Cl < F < O < S
(b) O < S < F < Cl
(c) F < S < O < Cl
(d) S < O < Cl < F
Answer. B

Question. Among the elements Ca, Mg, P and Cl, the order of increasing atomic radii is
(a) Mg < Ca < Cl < P
(b) Cl < P < Mg < Ca
(c) P < Cl < Ca < Mg
(d) Ca < Mg < P < Cl
Answer. B

Question. Among the following which one has the highest cation to anion size ratio?
(a) CsI
(b) CsF
(c) LiF
(d) NaF 
Answer. B

Question. Amongst the elements with following electronic configurations, which one of them may have the highest ionisation energy?
(a) Ne [3s²3p²]
(b) Ar [3d¹⁰4s² 4p³]
(c) Ne [3s² 3p¹]
(d) Ne [3s² 3p³] 
Answer. D

Question. Identify the correct order of the size of the following.
(a) Ca²⁺< K⁺< Ar < Cl^– < S^2–
(b) Ar < Ca²⁺ < K⁺ < Cl^– < S^2–
(c) Ca²⁺ < Ar < K+ < Cl– < S^2–
(d) Ca²⁺ < K+ < Ar < SS^2– < Cl^–
Answer. A

Question. With which of the following electronic configuration an atom has the lowest ionisation enthalpy?
(a) 1s²2s² 2p3
(b) 1s²2s² 2p⁵ 3s¹
(c) 1s² 2s² 2p6
(d) 1s² 2s² 2p⁵ 
Answer. B

Question. Which one of the following ionic species has the greatest proton affinity to form stable compound?
(a) NH₂^–
(b) F^–
(c) I^–
(d) HS^–
Answer. A

Question. Which of the following is the most basic oxide?
(a) SeO₂
(b) Al₂O₃
(c) Sb₂O₃
(d) Bi₂O₃
Answer. D

Question. What is the correct relationship between the pH of isomolar solutions of sodium oxide, Na₂O (pH₁), sodium sulphide, Na₂S (pH₂), sodium selenide, Na2Se (pH₃) and sodium telluride Na2Te (pH₄)?
(a) pH₁> pH₂> pH₃ > pH₄
(b) pH₁ > pH₂ ≈ pH₃ > pH₄
(c) pH₁ < pH₂ < pH₃ < pH₄
(d) pH₁ < pH₂ < pH₃ ≈ pH₄
Answer. A

Question. Ionic radii are
(a) inversely proportional to effective nuclear charge
(b) inversely proportional to square of effective nuclear charge
(c) directly proportional to effective nuclear charge
(d) directly proportional to square of effective nuclear charge. 
Answer. A

Question. The ions O^2–, F^–, Na⁺, Mg²⁺and Al³⁺are isoelectronic.
Their ionic radii show
(a) a significant increase from O^2– to Al³⁺
(b) a significant decrease from O^2– to Al³⁺
(c) an increase from O^2– to F^– and then decrease from Na⁺ to Al³⁺
(d) a decrease from O^2– to F^– and then increase from Na⁺ to Al³⁺. 
Answer. B

Question. Which of the following order is wrong?
(a) NH₃< PH₃< AsH₃ – acidic
(b) Li < Be < B < C – 1st IP
(c) Al₂O₃ < MgO < Na₂O < K₂O – basic
(d) Li⁺ < Na⁺ < K⁺ < Cs⁺ – ionic radius.
Answer. B

Question. Correct order of 1st ionisation potential among following elements Be, B, C, N, O is
(a) B < Be < C < O < N
(b) B < Be < C < N < O
(c) Be < B < C < N < O
(d) Be < B < C < O < N 
Answer. A

Question. Which of the following elements has the maximum electron affinity?
(a) I
(b) Br
(c) Cl
(d) F 
Answer. C

Question. The first ionization potentials (eV) of Be and B respectively are
(a) 8.29, 8.29
(b) 9.32, 9.32
(c) 8.29, 9.32
(d) 9.32, 8.29
Answer. D

Question. Which one of the following is correct order of the size of iodine species?
(a) I⁺> I– > I
(b) I– > I > I⁺
(c) I > I– > I+
(d) I > I⁺> I–
Answer. B

Question. Which of the following ions is the largest in size?
(a) K⁺
(b) Ca²⁺
(c) Cl^–
(d) S^2–
Answer. D

Question. Which of the following has the smallest size?
(a) Al³⁺
(b) F^–
(c) Na⁺
(d) Mg²⁺ 
Answer. A

Question. Among the following oxides, the one which is most basic is
(a) ZnO
(b) MgO
(c) Al₂O₃
(d) N₂O₅
Answer. B

Question. Which of the following has largest size?
(a) Na
(b) Na⁺
(c) Na^–
(d) Can’t be predicted.
Answer. C

Question. Na⁺, Mg²⁺, Al³⁺and Si⁴⁺are isoelectronic. The order of their ionic size is
(a) Na⁺ >Mg²⁺ < Al³⁺ < Si⁴⁺
(b) Na⁺ < Mg²⁺ > Al³⁺ > Si⁴⁺
(c) Na⁺ > Mg²⁺ > Al³⁺ > Si⁴⁺
(d) Na⁺ <Mg²⁺ > Al³⁺ < Si⁴⁺
Answer. C

Question. In the periodic table from left to right in a period, the atomic volume
(a) decreases
(b) increases
(c) remains same
(d) first decreases then increases. 
Answer. D

Question. Which electronic configuration of an element has abnormally high difference between second and third ionization energy?
(a) 1s², 2s², 2p⁶, 3s¹
(b) 1s², 2s², 2p⁶, 3s¹, 3p¹
(c) 1s², 2s², 2p⁶, 3s², 3p²
(d) 1s², 2s², 2p⁶, 3s²
Answer. D

Question. One of the characteristic properties of non-metals is that they
(a) are reducing agents
(b) form basic oxides
(c) form cations by electron gain
(d) are electronegative. 
Answer. D

Question. Which one of the following has minimum value of cation/anion ratio?
(a) NaCl
(b) KCl
(c) MgCl₂
(d) CaF₂
Answer. C

Question. Which of the following sets has strongest tendency to form anions?
(a) Ga, Ni, Tl
(b) Na, Mg, Al
(c) N, O, F
(d) V, Cr, Mn 
Answer. C

Question. Elements of which of the following groups will form anions most readily?
(a) Oxygen family
(b) Nitrogen family
(c) Halogens
(d) Alkali metals 
Answer. C

Question. In the periodic table, with the increase in atomic number, the metallic character of an element
(a) decreases in a period and increases in a group
(b) increases in a period and decreases in a group
(c) increases both in a period and the group
(d) decreases in a period and the group. 
Answer. A

Question. Which of the following atoms will have the smallest size?
(a) Mg
(b) Na
(c) Be
(d) Li
Answer. C