Answer:
The necessary energy that we must contribute to a neutral atom in the gas phase to release an electron. The plucked electron will be the outermost and will require less energy since it is far from the nucleus.
Step-by-step explanation:
The ionization energy increases in the periods of the periodic table and decreases in the groups. If the atom is very small, we will need a lot of energy to release the electron, while if the atom is larger the energy will be greater.