Which feature is shared by all resonance forms of a molecule or ion?

• A. The formal charges on each atom are the same in all resonance forms.
• B. The arrangement of atoms (connectivity) remains the same in all resonance forms.
• C. Each resonance form has a different number of total electrons.
• D. The placement of all electrons, including bonding and lone pairs, is identical in all resonance forms.

Answer: (B)

Verified step by step guidance

1. Understand that resonance forms are different Lewis structures representing the same molecule or ion, where only the placement of electrons changes, not the arrangement of atoms.
2. Recognize that in all resonance forms, the connectivity of atoms (which atoms are bonded to which) remains constant; atoms do not move or change their bonding partners.
3. Note that formal charges can differ between resonance forms, but the overall charge of the molecule or ion remains the same.
4. Realize that the total number of electrons is the same in all resonance forms, as they represent the same species, but the distribution of bonding and lone pair electrons can vary.
5. Conclude that the key shared feature of all resonance forms is the identical arrangement of atoms (connectivity), while electron placement can differ.