Which oneamong thefollowingelementshas thelowestfirstionisationenthalpyand which of thehashighestfirstionisationenthalpy? Li, K , Ca , S andKr.

Which oneamong thefollowingelementshas thelowestfirstionisationenthalp

1.	Which oneamong thefollowingelementshas thelowestfirstionisationenthalpyand which of thehashighestfirstionisationenthalpy? Li, K , Ca , S andKr.
Answer» Solution :Li belongs to the 2ndperiod. S TOTHE 3rdwhile K and Krbelongto the 4thperiod.BothLi and Kare ALKALI metalsbut the sizeof K isbiggerthan thatofLi . Furthersince alongany period, `Delta_(i) H_(1)` of alkalimetas is thelowestwhile of thatinertgas is THEHIGHEST. Thereforek hasthelowest`Delta_(i) H_(1)` while Krhas thehighest`Delta_(i) H_(1)`