Use Lewis structures to explain why Br₃^- and I₃^- are stable, while F₃^- is not.

Lewis structures are diagrams that represent the bonding between atoms in a molecule and the lone pairs of electrons that may exist. They help visualize the arrangement of electrons and the connectivity of atoms, which is crucial for understanding molecular stability and reactivity. By depicting valence electrons, Lewis structures allow chemists to predict the shape and polarity of molecules.

Resonance refers to the phenomenon where a molecule can be represented by two or more valid Lewis structures, which contribute to its overall stability. In the case of Br3- and I3-, resonance structures allow for delocalization of electrons, distributing charge more evenly and enhancing stability. In contrast, F3- lacks sufficient resonance structures to stabilize the negative charge effectively, leading to instability.

Formal charge is a theoretical charge assigned to an atom in a molecule, calculated based on the number of valence electrons, the number of bonds, and the number of lone electrons. It helps assess the most stable Lewis structure by minimizing formal charges across the molecule. For Br3- and I3-, the formal charges can be distributed favorably, while in F3-, the high electronegativity of fluorine leads to unfavorable formal charge distributions, contributing to its instability.