CBSE Class 11 Chemistry HOTs Classification of Elements and Periodicity in Properties

Question. Which form coloured salts?
(a) Non-metals
(b) Metals
(c) p-block elements
(d) Transitional elements
Answer : D

Question. What is the atomic number of the next halogen if discovered?
(a) 85
(b) 117
(c) 167
(d) 104
Answer : B

Question. The first ionisation potential in electron volts of nitrogen and oxygen atoms are respectively given by
(a) 14.6, 13.6
(b) 13.6, 14.6
(c) 13.6, 13.6
(d) 14.6, 14.6
Answer : A

Question. The electronic configuration of four elements are given below. Which elements does not belong to the same family as others?
(a) [Xe]4f¹⁴5d¹⁰ls²
(b) [Kr]4d¹⁰5s²
(c) [Ne]3s2³p⁵
(d) [Ar] 3d¹⁰ 4s²
Answer : C

Question. The electronic configuration of an element is 1s² 2s² 2 p6 3s² 3p³ . The atomic number and the group number of the element ‘X’ which is just below the above element in the periodic table are respectively
(a) 23 and 5
(b) 23 and 15
(c) 33 and 15
(d) 33 and 5
Answer : C

Question. Which of the following order is wrong?
(a) NH₃ < PH3 < AsH₃ – Acidic
(b) Li < Be < B < C – First IP
(c) Al₂O₃ < MgO < Na₂O < K₂O – Basic
(d) Li⁺ < Na⁺ < K⁺ < Cs⁺ – Ionic radius
Answer : B

Question. The ease of loss of electron from Ne and Na⁺ ion (both isoelectronic) are
(a) 4562 kJ mol^–1, 2081 kJ mol^–1
(b) 2081 kJ mol^–1, 4562 kJ mol^–1
(c) 2081 kJ mol^–1 each
(d) 4562 kJ mol^–1 each
Answer : B

Question. The elements with atomic numbers 9, 17, 35, 53 and 85 belong to
(a) alkali metals
(b) alkaline earth metals
(c) halogens
(d) noble gases
Answer : C

Question. In which of the following process highest energy is absorbed?
(a) Cu → Cu⁺
(b) Br → Br^-
(c) I → I^-
(d) Li → Li⁺
Answer : A

Question. The incorrect statement among the following is
(a) The first ionization potential of Al is less than the first ionization potential of Mg
(b) The second ionization potential of Mg is greater than the second ionization potential of Na
(c) The first ionization potential of Na is less than the first ionization potential of Mg
(d) The third ionization potential of Mg is greater than the third ionization potential of Al.
Answer : B

Question. The ionic radii of Na⁺, F^–, O^2–, N^3– follow the order
(a) O^2– > F^– > Na⁺ > N^3–
(b) N^3– > Na⁺ > F^– > O^2–
(c) N^3– > O^2– > F^– > Na⁺
(d) Na⁺ > F^– > O^2– > N^3–
Answer : C

Question. Which one of the following ions has the highest value of ionic radius ?
(a) O^2–
(b) B³⁺
(c) Li⁺
(d) F^–
Answer : A

Question. Amphoteric-oxide combinations are in
(a) ZnO, K₂O, SO₃
(b) ZnO, P₂O₅, Cl₂O₇
(c) SnO₂, Al₂O₃, ZnO
(d) PbO₂, SnO₂, SO₃
Answer : C

Question. Which ionisation potential (IP) in the following equations involves the greatest amount of energy?
(a) Na → Na⁺ + e^--
(b) K⁺ → K²⁺ + e^-
(c) C²⁺ → C³⁺ + e^-
(d) Ca⁺ → Ca²⁺ + e^-
Answer : B

Question. Eka-aluminium and Eka-silicon are known as
(a) gallium and germanium
(b) aluminium and silicon
(c) iron and sulphur
(d) manganese and magnesium
Answer : A

Question. The electron affinity for the inert gases is
(a) zero
(b) high
(c) negative
(d) positive
Answer : A

Question. The correct order of acidic strength :
(a) Cl₂O₇ > SO₂ > P4O₁₀
(b) K₂O > CaO > MgO
(c) CO₂ > N₂O₅ > SO₃
(d) Na₂O > MgO > Al₂O₃
Answer : A

Question. Electronic configurations of four elements A, B, C and D are given below :
(i) 1s² 2s² 2p⁶
(ii) 1s² 2s² 2p⁴
(iii) 1s² 2s² 2p⁶ 3s¹
(iv) 1s² 2s² 2p⁵
Which of the following is the correct order of increasing tendency to gain electron ?
(a) (i) < (iii) < (ii) < (iv)
(b) (i) < (ii) < (iii) < (iv)
(c) (iv) < (ii) < (iii) < (i)
(d) (iv) < (i) < (ii) < (iii)
Answer : A

Question. The formation of the oxide ion O^2–(g) requires first an exothermic and then an endothermic step as shown below :
O(g) + e^- = O^- (g) ΔHº= -142 kJmol^-1
O- (g) + e^- = O^2-(g) ΔHº = 844 kJmol^-1
This is because
(a) O– ion will tend to resist the addition of another electron
(b) Oxygen has high electron affinity
(c) Oxygen is more electronegative
(d) O– ion has comparatively larger size than oxygen atom
Answer : A

Question. The basic character of MgO, BaO, Na₂O and FeO follow the order
(a) MgO < FeO < BaO < Na₂O
(b) FeO < MgO < Na₂O < BaO
(c) FeO < MgO < BaO < Na₂O
(d) Na₂O < MgO < FeO < BaO
Answer : C

Numeric Value Answer

Question. What is the number of elements in the third period of the periodic table except metalloids?
Answer : 7

Question. In the IUPAC nomenclature of elements, what is atomic number for the element ‘Unh’?
Answer : 106

Question. How many completely filled periods are there in the long form of the periodic table ?
Answer : 7

Question. How many pairs are, in which first species has lower ionisation energy than second species:
(i) N and O             (ii) Br and K
(iii) Be and B        (iv) I and I^–
(iv) Li and Li⁺        (v) O and S
(vii) Ba and Sr
Answer : 2

Question. The first ionisation potential of Cu, Ag and Au are 731, 745 and 890 KJ/mol (not in the same order). What is the numerical value of I.E. for Ag?
Answer : 731