Answer:
Argon
Step-by-step explanation:
-Ionization energy is the energy that is required to remove an electron.
-Ionization energy increases as you go from left to right the periodic table and decreases as you go from top to bottom of the periodic table.
-The reason why argon has greater ionization energy is because it is very hard to remove as argon is a noble gases. We know noble gases are inactive because they are already stable. If you're stable, you are less likely to gain or lose electron.