Answer
See explanation.
Work Step by Step
The alkali metals have a weakly-bound s electron, and would not mind giving it up so that the atom can have a completed subshell and a noble-gas electron configuration. Hence it doesn’t take much energy to remove that outer electron.
On the other hand, the noble gases are already happy with their stable, completed electron configurations and it is more energetically unfavorable for them to give up an electron.
