Concept explainers
Interpretation: Any one structure from top row is enough to describe the molecule in top row but all structure is needed from bottom row to describe the molecule in bottom row should be explained.
Concept introduction: When one single structure is unable to describe all the properties of single molecule, a phenomenon called resonance comes into play. This arises when two or more than two Lewis structures are possible for one molecule. All such structures are called resonating structures and have same placement of atoms in them but these have different locations of bond pairs and lone pairs. The resonating structures are inter-convertible with each other. The resultant of all the resonating or contributing structures is called the resonance hybrid.
Rules to form resonance structure are as follows:
1. Use arrow types 1 and 2 for resonance structure of anions in movement of negative charge.
2. Use only arrow type 3 to move a positive charge for resonance structure of cations.
3. The sigma bond should not be broken. Any atom must not move from its place and total number of electrons must be same in all resonance structures.
Want to see the full answer?
Check out a sample textbook solutionChapter 5 Solutions
Organic Chemistry: A Guided Inquiry
- Doxorubicin, shown here, is an important chemotherapy drug used to treat avariety of cancers, including bladder cancer, breast cancer, and certain forms of leukemia. Doxorubicin works by binding to DNA in such a way that a portion of it penetrates the DNA double helix— a process called intercalation. During transcription— the process that forms RNA— portions of the DNA strands are temporarily separated for the base sequence to be read and then are reconnected. With bound doxorubicin, however, the double helix does not reform properly after the strands are separated, which disrupts replication— the process that forms an identical copy of DNA. Which portion of doxorubicin do you think intercalates into the DNA double helix, and why do you think it has little difficulty doing so?arrow_forwardDraw the best Lewis structure for the linear C ion, including all lone pair electrons and non-zero formal charges.arrow_forwardDraw a Lewis structure of your choice that has at least three equally reasonable resonance structures. You must show your work as to how the structure was drawn including showing valence electrons, any structures you draw that don’t work and require you to show a multiple bond, and formal charges on each atom that has a formal charge. For example, Nitrate ion has three structures (but you can’t draw this one). All three structures have formal charges and no one structure is preferred based on formal charge. Carbon dioxide would not be a valid choice. While it does have three structures, the structure that has two double bonds is the preferred structure while the structures with triple bonds are not equivalent to the double bonded version as they have multiple formal charges present.arrow_forward
- Consider compounds A–D, which contain both a heteroatom and a double bond. (a) For which compounds are no additional Lewis structures possible? (b) When two or more Lewis structures can be drawn, draw all additional resonance structures.arrow_forwardTwo major resonance structures are possible for the anion shown. One resonance form is given, but it is incomplete. Complete the given structure by adding nonbonding electrons and formal charges. Draw the remaining structure, including nonbonding electrons and formal charges. Omit curved arrows. Structure A: complete the structure by adding nonbonding electrons and formal charges. H H H I Structure B: draw the remaining resonance structure, including nonbonding electrons and formal charges. H- : z: H Harrow_forwardThe structure of Vitamin C (ascorbic acid) is shown below. As the name indicates, the molecule is somewhat acidic. Actually, one of the hydrogens on the four OH groups is much more acidic than the other three ones. Which one is the acidic hydrogen? Hints: To find the answer, you will again have to draw some resonance structures of the product formed after loss of H+. Consider the product after the loss of H+ for each of the OH groups. Only two of the OH groups have resonance structures after deprotonation; one of these two groups has a much better resonance structure than the other one (again after deprotonation). Note that the oxygen atom that is part of the five-membered ring has nothing to do with the problem.arrow_forward
- How do you know when to draw a solid wedge vs a dashed wedge when drawing 3D bond-line structures? I know that solid-wedge means the atom is pointing towards you and dashed wedge means it's in the back, but how do you know which atoms are in the front as opposed to the back? How can you tell what the configuration will look like in space just by looking at the lewis structure or name?arrow_forwardWhich of the following shows correct arrow placement that represents significant resonance for the given molecule? None of the choices given represent significant resonance. Save for Laterarrow_forwardChemistry (a) Write three more resonance structures for each of compounds 1 and 2. (b) In each of compounds 1 and 2, determine which resonance structure contributes the most and explain your answer. (c) Are the 3/4 structures resonance structures or different compounds? Same question for 5/6 structures. Explain your answers.arrow_forward
- Which of the following species is a valid resonance structure of A? Use curved arrows to show how A is converted to any valid resonance structure. When a compound is not a valid resonance structure of A, explain why not.arrow_forwardWhat would the resonance structure of these 2 compounds be? And which would be the major?arrow_forwardConsider compounds A–D, which contain both a heteroatom and a double bond. (a) For which compounds are no additional Lewis structures possible? (b) When two or more Lewis structures can be drawn, draw all additional resonance structures.arrow_forward
- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage LearningChemistry: The Molecular ScienceChemistryISBN:9781285199047Author:John W. Moore, Conrad L. StanitskiPublisher:Cengage Learning