The first $$\left( {{\Delta _i}{H_1}} \right)$$ and second $$\left( {{\Delta _i}{H_2}} \right)$$ ionization enthalpies $$\left( {{\text{in}}\,kJ\,mo{l^{ - 1}}} \right)$$ and the electron gain enthalpy $$\left( {{\Delta _{eg}}H} \right)\left( {{\text{in}}\,kJ\,mo{l^{ - 1}}} \right)$$ of the elements (i), (ii), (iii),(iv) and (v) are given below.
$$\eqalign{
& {\text{Element}}\,\,\,\,{\Delta _i}{H_1}\,\,\,{\Delta _i}{H_2}\,\,\,\,\,\,{\Delta _{eg}}H \cr
& \left( {\text{i}} \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,520\,\,\,\,\,\,\,\,\,7300\,\,\,\,\,\, - 60 \cr
& \left( {{\text{ii}}} \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,419\,\,\,\,\,\,\,\,\,3051\,\,\,\,\,\, - 48 \cr
& \left( {{\text{iii}}} \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,1681\,\,\,\,\,\,\,3374\,\,\,\,\, - 328 \cr
& \left( {{\text{iv}}} \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,1008\,\,\,\,\,\,\,1846\,\,\,\,\, - 295 \cr
& \left( {\text{v}} \right)\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,2372\,\,\,\,\,\,\,5251\,\,\,\,\,\, + 48 \cr} $$
The most reactive metal and the least reactive non-metal of these are respectively
A.
(i) and (v)
B.
(v) and (ii)
C.
(ii) and (v)
D.
(iv) and (v)
Answer :
(ii) and (v)
Solution :
(i) represents $$Li,$$ (ii) represents $$K$$
(iii) represents $$Br,$$ (iv) represents $$I$$
(v) represents $$He$$
So, amongst these, (ii) represents most reactive metal and (v) represents least reactive non-metal.
Releted MCQ Question on Inorganic Chemistry >> Classification of Elements and Periodicity in Properties
Releted Question 1
The correct order of second ionisation potential of carbon, nitrogen, oxygen and fluorine is