Answer:
F < O < Cl
Explanation:
Fluorine has a greater effective nuclear charge than oxygen does, meaning that the electrons are drawn tighter and closer toward the nucleus. Fluorine has 9 protons and 9 electrons while oxygen only has 8 protons and electrons. Chlorine has a larger atomic radius than both fluorine and chlorine because has another energy level (shell). Although chlorine has the same effective nuclear charge as fluorine, chlorine has more electrons, 17, which requires an additional shell to contain them.
