Within a group on the periodic table, where would you expect the ionization energy to be the greatest?

• A. At the top of the group
• B. At the bottom of the group
• C. In the middle of the group
• D. Ionization energy is the same throughout the group

Answer: (A)

Verified step by step guidance

1. Recall that ionization energy is the energy required to remove an electron from an atom in the gaseous state.
2. Understand that within a group (column) on the periodic table, atoms have the same number of valence electrons but increasing numbers of electron shells as you move down the group.
3. Recognize that as you move down a group, the outermost electrons are farther from the nucleus and experience more shielding from inner electrons, which lowers the ionization energy.
4. Therefore, ionization energy decreases as you go down a group because it becomes easier to remove an electron from atoms with more electron shells.
5. Conclude that the ionization energy is greatest at the top of the group, where the outer electrons are closest to the nucleus and experience less shielding.