Modern periodic law and periodic table, s, p, d, f blocks
- Which among the following electronic configurations belong to main group elements?A. [Ne]3s^1 B. [Ar]3d^3 4s^2 C. [Kr]4d^105s^2 5p^5 D. [Ar]3d^104s^1 E. [Rn]5f^0 6d^2 7s^2Choose the correct answer from the option given below : Answer: 2. A and C only Key idea: main group elements are s- and p-block elements; d-block elements have d electrons being filled. A: [Ne]3s... 1
- Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R :Assertion A : Metallic sodium dissolves in liquid ammonia giving a deep blue solution, which is paramagnetic.Reasons R : The deep blue solution is… Answer: 4. A is true but R is false. Key idea: Sodium in liquid ammonia gives ammoniated electrons. Na + (x+y)NH₃ → [Na(NH₃)_x]^+ + [e(NH₃)_... 1
- Which one of the following statements is correct? Answer: 2. The daily requirement of Mg and Ca in the human body is estimated to be 0.2 - 0.3 g. Key idea: Recall the biological roles of Mg... 1
- Match List - I with List - II.List - I: (a) Li (b) Na (c) KOH (d) CsList - II: (i) absorbent for carbon dioxide (ii) electrochemical cells (iii) coolant in fast breeder reactors (iv) photoelectric cellChoose the correct answer from the options given… Answer: 1. (a) - (ii), (b) - (iii), (c) - (i), (d) - (iv) Key idea: recall the uses of alkali metals and their compounds. Li: electrochemica... 1
- Identify the incorrect statement from the following Answer: 3. The oxidation number of K in KO₂ is +4 . Key idea: in superoxide KO₂ , oxygen is O₂^- , so K is +1. Alkali metals always show +1.... 1
- The IUPAC name of an element with atomic number 119 is Answer: 2. ununennium Key idea: IUPAC temporary names use numerical roots: 0 = nil, 1 = un, 9 = enn, ending in -ium. Z = 119 means digits 1,... 1
- Identify the incorrect match.Name | IUPAC Official Name(a) Unnilunium | (i) Mendelevium(b) Unniltrium | (ii) Lawrencium(c) Unnilhexium | (iii) Seaborgium(d) Unununnium | (iv) Darmstadtium Answer: 4. (d), (iv) IUPAC temporary names come from the atomic number: un=1, nil=0, tri=3, hex=6. Unnilunium = 101 = Mendelevium. Match (a)... 1
- The element Z = 114 has been discovered recently. It will belong to which of the following family/group and electronic configuration ? Answer: 1. Carbon family, [Rn] 5f¹⁴6d¹⁰7s²7p² Key idea: element 114 lies in the same group as Pb (Z = 82), one period lower, so its outer sh... 1
- The suspension of slaked lime in water is known as Answer: 2. milk of lime Key idea: Ca(OH)₂ is only sparingly soluble in water. A suspension of slaked lime in water looks milky, so it is cal... 1
- Which of the following statements is false ? Answer: 3. Ca²⁺ ions are not important in maintaining the regular beating of the heart. Key idea: mathrmCa²⁺ and mathrmMg²⁺ both have import... 1
- Which of the following statements about hydrogen is incorrect ? Answer: 1. Hydrogen has three isotopes of which tritium is the most common. Key idea: check each statement against NCERT facts and pick the... 1