Among Be ,B,Mg andA1 thesecondionizationpotential ismaximumfor

1.	Among Be ,B,Mg andA1 thesecondionizationpotential ismaximumfor
Answer» B Be Mg A1 Solution :The E.Csofthe ionsobtainedafterremovalof firstelectronfrom theseelementsare `: Be^(+)(1s^(2)2s^(1))` `B^(+) (1s^(2)2s^(2) ) ,Mg^(+)(1s^(2)2s^(2)3s^(1))` and `A1^(+)(1s^(2) 2p^(2)2p^(6)3s^(2))` Since`Mg^(+)` and `A1^(+)` belongto 3rdperiodwhile `Be^(+)` and `B^(+)`belongto 2ndperiod , thereforedue tobiggersize the`Delta_(i)H_(2) `of `Mg^(+)` and `A1^(+)` are lowerthan thoseof `Be^(+)`and `B^(+)` Since `B^(+)`the nextelectronhas to beremovedfrom amorestabletally filled 2s-orbital whilein`Be^(+)` it has to belost fromthe lessstable hafl- filled2s- orbital adn furthermore LOSS of anelectronfrom `Be^(+)` givesmorestable `Be^(2+)` ion withinet gasconfigurationtherefore`Delta_(i)H_(2)` ofB ishigherthanthat of Be , i.e.,option( a) ISCORRECT.

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