Which of the elements show least values of ionisation within their periods ?

Which of the elements show least values of ionisation energies within their periods?

The element with highest value of ionisation potential is

Which group of elements shows lowest ionisation enthalpy?

Which group of elements shows lowest ionisation enthalpy?

Which among the following elements has lowest value of ionisation potential ?

Which among the following elements has lowest value of ionisation potential ?

Assertion : Alkali metals have least value of ionization energy within a period. Reason : They precede alkaline earth metals in periodic table.

Which of the following rare gases shows least ionisation potential ?