Final answer:
The ionization energy needed to remove the next electron from an atom increases with each electron that is removed due to the increasing nuclear charge and decreasing size of the atom.
Step-by-step explanation:
The ionization energy needed to remove the next electron from an atom increases with each electron that is removed primarily due to the increasing nuclear charge and decreasing size of the atom. As we move from left to right across the periodic table, the number of protons in the nucleus increases, resulting in a stronger attraction between the nucleus and the electrons. This stronger attraction makes it more difficult to remove electrons, leading to an increase in ionization energy.
For example, when removing the first electron from a neutral atom, it is farther away from the nucleus and experiences less electrostatic attraction. However, the second electron is closer to the nucleus and is held more tightly, requiring more energy to remove. This trend continues as more electrons are removed, with each successive electron being held even more tightly by the positively charged nucleus.