What is the difference between the electron group geometry and the molecular geometry?

Which of the following elements would you expect to have the highest ionization energy value, and why? a. chlorine (cl), because it has a low effective nuclear charge and large radius b. fluorine (f), because it has a large radius and naturally forms a negative ion c. lithium (li), because it has a small radius and naturally forms a positive ion d. neon (ne), because it has a high effective nuclear charge and small radius