The first `(DeltaiH1)` and the second `(DeltaiH2)` ionization enthalpies `("in kJ mol"^(-1))` and the `(DeltaegH)` electron gain enthalpy `("in kJ mol"^(-1))` of a few elements are given below:
`{:("Elements", DeltaH1 ,DeltaH2 ,Delta_(eg)H) ,(I ,520, 7300, –60),(II ,419 ,3051 ,–48),(III ,1681 ,3374 ,–328),(IV ,1008 ,1846 ,–295),(V ,2372 ,5251, +48),(VI ,738 ,1451, –40):}`
Which of the above elements is likely to be : (a) the least reactive element.
(b) the most reactive metal.
(c) the most reactive non-metal.
(d) the least reactive non-metal.
(e) the metal which can form a stable binary halide of the formula `MX_(2)`(X=halogen).
(f) the metal which can form a predominantly stable covalent halide of the formula MX (X=halogen)?

Options

A. R
B. S
C. P
D. U

Answer

A

Explanation

Non-metal having higher negative value of electron gain enthalpy corresponds to halogen.Hence R is more reactive non-metal (easily forms anion)