Match the correct ionisation enthalpies and electron gain enthalpies of the following elements.

Answer

A

Explanation

(i) Most reactive non-metal has high, `Delta_(i)H_(1)` and `Delta_(i)H_(2)` and most negative `Delta_(eg)H`. Therefore, the element is B.
(ii) Most reactive metal has low `Delta_(i)H_(1)` and high `Delta_(i)H_(2)` (because the second electron has to be lost from noble gas configuration) and has small negative `Delta_(eg)H`. Therefore, the element is A.
(iii) Least reactive element has higher `Delta_(i)H_(1)` and `Delta_(i)H_(2)` and has positive `Delta_(eg)H` values. Thus, the element is D.
iv) Metal forming binary halides are alkaline earth metals. They have `Delta_(i)H_(1)` and `Delta_(i)H_(2)` values little higher than those of most reactive metals (such as A) and have comparatively slightly less negative `Delta_(eg)H` values. Thus, the element is C.