Question 1
What is the first ionization energy of an element?
The right answer is the one marked above.
The minimum energy that must be supplied to remove an electron from an atom of the element in the gaseous state, forming a gaseous unipositive ion.
Every part of that definition is doing work. Minimum, because less will not do it. Gaseous, because the atoms must be free of one another for the measurement to mean anything. And unipositive, because exactly one electron leaves.