Question 1

The correct statement(s) regarding the periodic properties of elements is(are)

Accepted Answer

For (A): The electronic configuration of B ^+ is 1s^2 2s^2 and that of C ^+ is 1s^2 2s^2 2p^1. Removing an electron from the fully filled, more penetrating 2s orbital of B ^+ requires more energy than removing a 2p electron from C ^+. Thus, the second ionization enthalpy of carbon is less than that of boron. Statement (A) is correct. For (B): Al ^ 3+ , Mg ^ 2+ , and Na ^+ are isoelectronic species with 10 electrons each. The nuclear charge increases in the order Na ^+ (11) For (C): The density o

Question 2

The 1 st , 2 nd and the 3 rd ionization enthalpies, I 1 , &#160; I 2  and  I 3 , of four atoms with atomic numbers  n , &#160; n + 1 , &#160; n + 2 , and n + 3 , where n &#60; 10 , are

Accepted Answer

From given data ( n + 2 ) atom is alkali metal which is sodium. As  n + 2 = 11 So,  n = 9

Classification of Elements and Periodicity in Properties — Previous Year Questions & Solutions