Classification of Elements and Periodicity in Properties
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See all →- Which of the following statements are true?A. Unlike Ga that has a very high melting point, Cs has a very low melting point.B. On Pauling scale, the electronegativity values of N and Cl are not the same.C. Ar, K^+, Cl^-, Ca^2+, and S^2- are all isoel… Answer: 2. C and E only Key idea: check each statement separately. A false: gallium melts at only about 30 °C, so it does not have a very hi... 1
- 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
- Arrange the following elements in increasing order of first ionization enthalpy:Li, Be, B, C, NChoose the correct answer from the options given below: Answer: 3. Li < B < Be < C < N Key idea: ionization enthalpy increases across a period, with exceptions at Be (filled 2s) and N (half-filled... 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
- The element expected to form largest ion to achieve the nearest noble gas configuration is : Answer: 4. N Key idea: For isoelectronic ions (all 10 electrons), the one with the lowest nuclear charge is the largest. The ions are Na^+ (... 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