In which of the following options order of arrangement does not agree with the variation of property indicated against it ? A) `Al^(3+) lt Mg^(2+) lt Na^(+) lt F^(-)` (increasing ionic size) B)`B lt C lt N lt O` (increasing first ionisation enthalpy) C)`I lt Br lt Cl lt F` (increasing electron gain enthalpy) D)`Li lt Na lt K lt Rb` (increasing metallic radius)

Options

A. `A1^(3+) lt Mg^(2+) lt Na^(+) lt F^(-)` ( increasing ionic size )
B. `B lt C lt N lt O ` (increasing first ionisation enthalpy )
C. `I lt Br lt C lt F` (increasing electron gain enthalpy )
D. `Li lt Na lt K lt Rb` (increasing metallic radius )

Answer

B, C

Explanation

the ionic size increases as the + Ve charge on the cation decreases or the -ve charge on the anion increase
Therefore option (a) is correct.
than that of O.Thus option (b) is incorrect.
Due to greater stability of the half-filled electronic configuration or of N its ionization enthalpy is higher than that of O. Thus option ( b) is incorrect.
Dut to stronger electron- electron repulsion in thed small size of F the negative electron gain enthalpy of F is lower than that of C1 .Thus option ( c) is incorrect.
The metallic character increases as the size of the metallic atom increase . thus option (d) is correct.
Thus options ( b) and (c) are incorrect.