Periodicproperties show aregular gradation onmovingfrom leftto rightin aperiodor fromtoptobottomin a group . Downa groupthe atomicionicradii, metalliccharacterand reducing characterincreasewhileionizationenthalpyand electronegativitydecrease. Alonga periodfrom leftto rightatomic ionicradiiand metalliccharacterdecrease whileionizationenthalpyelectronegativitynon- metalliccharacterand oxidisingpowerincreases. However ,electrongainenthalpybecomesless negativedown agroupbut morenegativealonga period. Incontrastinertgaseshavepositiveelectrongainenthalpies whichdo not showanyregular trend .Amongst the followingelements(whoseelectronicconfigurationare givenbelow ) theone havingthe highestionizationenthalpy is :

Periodicproperties show aregular gradation onmovingfrom leftto rightin

1.	Periodicproperties show aregular gradation onmovingfrom leftto rightin aperiodor fromtoptobottomin a group . Downa groupthe atomicionicradii, metalliccharacterand reducing characterincreasewhileionizationenthalpyand electronegativitydecrease. Alonga periodfrom leftto rightatomic ionicradiiand metalliccharacterdecrease whileionizationenthalpyelectronegativitynon- metalliccharacterand oxidisingpowerincreases. However ,electrongainenthalpybecomesless negativedown agroupbut morenegativealonga period. Incontrastinertgaseshavepositiveelectrongainenthalpies whichdo not showanyregular trend .Amongst the followingelements(whoseelectronicconfigurationare givenbelow ) theone havingthe highestionizationenthalpy is :
Answer» `[Ne] 3 s^(2)3p^(1)` `[Ne] 3S^(2)3p^(3)` `[Ne] 3s^(2)3p^(2)` `[Ar] 3d^(10)4s^(2)4P^(3)` Solution :Both (b) and ( d)havesimilarexactly HALF- filledelectronicconfigurationbut thesizeof ( b)is smallerthat that of ( d) .