Question

Which group of elements shows lowest ionisation enthalpy?

• A. Alkali metals
• B. Alkaline earth metals
• C. Halogens
• D. Noble gases

Answer 1

The correct option is A Alkali metals

Group 1 elements show the lowest ionization enthalpy as they are biggest in the given period and it has the lowest effective nuclear charge than the rest elements of the period. It further decreases as we move down the group. Thus Alkali metals have lowest IE.

Hence, the correct option is $\text{A}$