Drawing resonance contributors helps to visualize and understand the electron distribution in a molecule. It also allows us to predict the reactivity and stability of the compound.
The major resonance contributor is the one that contributes the most to the overall stability of the compound. It is usually the one with the most complete octet and the least formal charges. The minor resonance contributors are those with less stability and may have more formal charges or incomplete octets.
There are a few rules to follow when drawing resonance contributors. First, all atoms must have a complete octet (except for hydrogen, which can have 2 electrons). Second, the overall charge of the molecule should stay the same. Third, only pi bonds and lone pairs can be moved to create resonance structures.
No, a molecule can only have a finite number of resonance contributors. This is because there are limitations to how many electrons can be moved and how many double bonds can be formed. Additionally, not all resonance structures are equally stable, so only the most significant ones are considered.
No, not all molecules have resonance contributors. Only molecules with delocalized electrons, such as those with pi bonds or lone pairs, can have resonance structures. Molecules with only single bonds or with all atoms having a complete octet do not have resonance contributors.