But with this new structure, all atoms have 8 electrons on their outer shell. Which of the following are resonance structures for nitrite ion, NO2? It's not common to have an odd number of valence electrons in a Lewis structure. Use curved arrows to show the flow of electrons in the resonance structures of 2,4-pentanedione anion below. There are three resonance structures for nitrate (NO3-) ... it depends which oxygen you choose to be double-bonded to the nitrogen. When trying to fry onions, the edges burn instead of the onions frying up. Using Formal Charge Calculations Determine Which Of The Three Is The Most Stable. (some say that octet is not fulfilled for nitrogen, but, for the first two reasonace structures also nitrogen doesn't have its octet filled). draw the lewis structure for NO2- including any valid resonance structures. You can view video lessons to learn Resonance Structures. In every case the actual molecule is found to be energetically more stable than would be expected from any of its resonance structures… Expert Answer . It means that for each covalent bond $\ce{A-B}$, there are $2$ electrons on the outer shell of $\ce{A}$ and of $\ce{B}$. Use MathJax to format equations. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Which of the following are resonance structures for nitrite ion, NO2? N 2 O Lewis Structure, Resonance Structures, Oxidation Number. In nitrite ion, NO2-, there are two equivalent resonance structures. Share to Twitter Share to Facebook Share to Pinterest. - 801900 Was Stan Lee in the second diner scene in the movie Superman 2? Get more help from Chegg. The actual is where N has 1.5 bonds to each O on average. For appropriate choice of system parameters, the natural frequency of the second mode is approximately twice that of the first providing the condition for 2 : 1 internal resonance. Making statements based on opinion; back them up with references or personal experience. The +1 positive charge within NO2+ is present on the central nitrogen atom which is the least electronegative species in the molecule (3.04 vs. oxygen's 3.44). One has an O⁻ on the left. When you draw Lewis structures for the nitrite ion, you find that you can draw two equivalent structures. hope this answer helps u 10-- (a) (c) ÖN_ (b) Oь Ос a&b Ob&c all are correctly drawn structures for the nitrite ion. Resonance and resonance hybrid structures of O3, SO3, SO2, CO3-2, SO4-2, PO4-2,NO3- he phenomenon of resonance was put forward by Heisenberg to explain the properties of certain covalent molecules. For Nitrogen we have 5 valence electrons; 6 for Oxygen, but we have two Oxygens so we'll multiply that by two; plus one for this valence electron up here; gives us a total of 18 valence electrons for the NO2- … Write 3D structures for all resonance contributors. In the nitrite ion, the bond lengths of both nitrogen-oxygen bonds are equal. Thanks for contributing an answer to Chemistry Stack Exchange! a. the nitrite ion contains 2 N-O bonds that are equivalent to 1 1/2 bonds. Newer Post Older Post Home. Interface damage and oxidation behavior are compared for electron cyclotron resonance plasma oxidation of silicon for two different plasma system configurations: a conventional system where the plasma is generated and extracted normal to the Si wafer surface, and another system where the plasma is made uniform by developing the magnetic field ... Electron spin resonance (ESR) was used to examine interactions of 16- Doxyl stearic acid in wheat starch-water (starch:water "'1: 1), vital wheat gluten-water and glut en-starch-water model systems, Immobilization of the 16-Doxyl stearic acid, shown by broadIine ESR powder patterns , occurred in wheat starch model systems. To learn more, see our tips on writing great answers. The actual distribution of electrons in each of the nitrogen-oxygen bonds in \(\ce{NO2-}\) is the average of a double bond and a single bond. None of these structures can exactly describe all the properties of the molecule, but each structure contributes to the true structure of the molecule. ...gave me (the) strength and inspiration to, I made mistakes during a project, which has resulted in the client denying payment to my company, Colour rule for multiple buttons in a complex platform. Such different structures are called 'resonance structures' and the actual molecule is termed as the 'resonance hybrid' of all these structures. H2COH H2CNH2 H2CCHO (CH3)2COH (CH3)2CNHCH3 (CH3)2CCH2CH3 Each N-O bond order in NO2- is 1.5. The doublet of the second bond between N and O has to be moved to the outer shell of oxygen, which becomes negatively charged, because one electron of this bond is coming from nitrogen atom. resonance structure of so3 and no2, Nonlinear dynamics of a viscoelastic buckled beam subjected to primary resonance in the presence of internal resonance is investigated for the first time. Nitrogen Dioxide (NO2) is a covalent compound that is composed of a central nitrogen atom single bonded to an oxygen atom and a double bond with another oxygen atom. We say we can draw two equivalent … Resonance structures are more stable than one single and one double bond. Both formulas represent the same number of atoms and electrons, just in a slightly different conformation. By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. So,isn't there one remaining electron? A step-by-step explanation of how to draw the NO2 + Lewis Structure (Nitronium Ion). We call the individual Lewis structures resonance forms. As with all other Lewis Dot Structures the bonds within the structure can be replaced by two dots. Neither is. What keeps the cookie in my coffee from moving when I rotate the cup? So, those are the two resonance structures. The b… Resonance structures are the possible structures of a molecule.For NO2,all my textbooks say they have only two resonance structures(2 possible Lewis structures) fulfilling octet rule(except for nitrogen,oxygen atoms does have octet),but a third structure can also be drawn as i have given below (which also fulfills octet for both oxygen atoms); So, those are the two resonance structures. The nitrite ion contains two N-O double bonds. Pour un grand nombre de composé, il est possible d'écrire plusieurs formules de Lewis pertinentes sans pour autant modifier la disposition spatiale des noyaux. Can nitrite (NO2) have a third resonance structure as i have given below. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. When we can say 0 and 1 in digital electronic? So in this case, both resonances structures contribute equally to the final structure of the molecule. Answer : The bond order of and are, 1.5 and 1 respectively. If $\ce{N}$ is surrounded by $4$ covalent bonds, each $\ce{N}$ atoms is surrounded by $ 8$ electrons. Forming the resonance structures for the nitrite anion, Confused about identifying delocalized electron pairs in Isoniazid. NO3^- ..... 2 single, 1 double, three resonance structures in order to follow the octet rule. Anytime you have more than one valid structure for a molecule or ion, you have what are known as resonance structures. Note that because all three oxygen atoms are really equivalent, the double bond could be written between the nitrogen atom and any of the three oxygen atoms. The actual structure is neither of these. The negative formal charge falls on the nitrogen atom. How can you come out dry from the Sea of Knowledge? When you draw resonance structures in your head, think about what that means for the hybrid, and how the resonance structures would contribute to the overall hybrid. Does a private citizen in the US have the right to make a "Contact the Police" poster? Write resonance structures for the following: NO 3-1. If not, why? Write the resonance structures for SO 3, NO 2 and . Asking for help, clarification, or responding to other answers. Answer : The bond order of and are, 1.5 and 1 respectively. Similarly in nitrate ion, NO3-, there are three equivalent resonance structures. The Lewis structure is O=N-O with two electron pairs on the left O and 3 electron pairs on the right O and one electron pair on the N. But you could also draw it as O-N=O. There is a resonance structure that can be drawn. So which one is the correct structure. Our tutors have indicated that to solve this problem you will need to apply the Resonance Structures concept. Resonance structures are the possible structures of a molecule.For NO2,all my textbooks say they have only two resonance structures(2 possible Lewis structures) fulfilling octet rule(except for nitrogen,oxygen atoms does have octet),but a third structure can also be drawn as i have given below (which also fulfills octet for both oxygen atoms); N have an odd lone electron and the oxygen atoms have 2 lone pairs of electron each. Explain the important aspects of resonance with reference to the CO3^2- ion. For these, minimizing the formal charges is more advantageous than drawing resonance structures. The binding in these complexes resembles that in the \(\pi\) complexes of halogens with alkenes and benzene (Sections 22-4D and 10-3C) and results from attractive forces between electron-rich and electron-poor substances. The actual structure is an equal mixture of the 3 resonance structures. 2) NO3– There are 3 possible resonance structures that satisfy the octet rule. Is "gate to heaven" "foris paradisi" or "foris paradiso"? NO 2 is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the production of fertilizers.At higher temperatures it is a reddish-brown gas. Email This BlogThis! When the two hydrogen atoms approach each … asked Oct 4, 2017 in Chemistry by jisu zahaan (29.7k points) chemical bonding and molecular structure; cbse +1 vote. Each N-O bond order in NO2- is 1.5. However, its measured structure is consistent with a description as a resonance hybrid of the two major contributing structures shown above: it has two equal N–O bonds of 125 pm, intermediate in length between a typical N–O single bond (145 pm in hydroxylamine, H 2 N–OH) and N–O double bond (115 pm in nitronium ion, [O=N=O] +). The Lewis structure for certain molecules or ions can be drawn in more than one way. It is a resonance hybrid of them both. MathJax reference. Indicate which has the strongest carbon-oxygen bond. In the contrary, canonical structure (II) of $\ce{HNO2}$ is very instable as the +ve charge is present on more electronegative element … What is the difficulty of this problem? Explain. I'll do NO2- as an example. When nitrous acid is dissolved in water, it produces H3O+1 ions and NO2-1 ions. Answer to: Draw all possible resonance structures for NO2-. Only 4 electrons is used for bonding,but isn't the number of valence electrons of nitrogen five? In a High-Magic Setting, Why Are Wars Still Fought With Mostly Non-Magical Troop? How to rationalise the resonance structures of nitrogen dioxide? Is it illegal to market a product as if it would protect against something, while never making explicit claims? It is: "hydroperoxyl radical or perhydroxyl radical, is the protonated form of superoxide" Since it has 13 electrons, you are going to have a difficult time obeying the rules for Lewis structures. Draw the Lewis structure for the nitrite ion (NO2) including any valid equivalent resonance structures. Solved Be Sure To Answer All Parts Draw Lewis Structures. Is there any role today that would justify building a large single dish radio telescope to replace Arecibo? Or if you need more Resonance Structures practice, you can also practice Resonance Structures practice problems. The $\ce{N-O}$ bonds in the $\ce{NO2-}$ ion are equal in length, whereas they are unequal in $\ce{HNO2}$. The NO2 Lewis structure has a total of 17 valence electrons. Resonance structures are useful to stay within the confines of the "octet rule." In nitrite ion, NO2-, there are two equivalent resonance structures. The nitrite ion contains two NO bonds and each one is equivalent to 1.5 bonds. Answer and Explanation: Nitrite ( NO− 2 N O 2 −) has 2 resonance structures shown below by moving the location of the double bond. at May 02, 2019. The other has an O⁻ on the right. Since the nitrogen dioxide ion has resonance, the $\ce{N-O}$ bonds are equal as resonance is in reality a hybrid of all of the possible structures for a certain molecule. (a) CO 2 (b) CO. Toothpastes containing sodium hydrogen carbonate (sodium bicarbonate) and hydrogen peroxide are widely used. The nitrite ion has two resonance structures. Write the Lewis structures for the following, and include resonance structures where appropriate. This is my explanation of how resonance occurs in the symmetrical nitrite ion, but not in the unsymmetrical nitrous acid molecule. Each N-O bond order in NO2- is 1.5. The actual is where N has 1.5 bonds to each O on average. Get more help from Chegg. So don't forget about your brackets, and your double-headed arrows, and also your formal charges, so you have to put those in, when you're drawing your resonance structures. Structure B: électron célibataire sur O. Atome central : N : 2s 2 2p 3 : 5 électrons . Nitrogen dioxide is a paramagnetic, bent molecule with C 2v point group symmetry Nitrogen dioxide is a chemical compound with the formula NO 2.It is one of several nitrogen oxides. See the Big List of Lewis Structures Transcript: This is the NO2- Lewis structure: the nitrite ion. Each N-O bond order in NO2- is 1.5. What Will The Hybridisation Of No2 Quora. And the actual electronic structure of the molecule is called resonance hybrid of the resonance forms. I also go over hybridization, shape and bond angles. $\ce{NO2^+}$ does exist with this structure, but not $\ce{NO2}$. Similarly in nitrate ion, NO3-, there are three equivalent resonance structures. No comments: Post a comment. For the NO2 Lewis structure, calculate the total number of valence electrons for the NO2 molecule. For appropriate choice of system parameters, the natural frequency of the second mode is approximately twice that of the first providing the condition for 2 : 1 internal resonance. chemistry.stackexchange.com/questions/105545/…, chemistry.stackexchange.com/questions/115078/…, chemistry.stackexchange.com/questions/9448/…. Home >> Text Solution >> Chemical Bonding and Molecular Structure >> write the resonance structures for so3 no2 and Question 13. Judge your structures on the basis of 1. maximum number of bonds / full octets, 2. minimize formal charge, 3, consistent formal charge based on electronegativity. Featured on Meta MAINTENANCE WARNING: … Why are engine blocks so robust apart from containing high pressure? Write the resonance structures for SO3, NO2 and NO3 -, CO2.,CO. This is … Note that because all three oxygen atoms are really equivalent, the double bond could be written between the nitrogen atom and any of the three oxygen atoms. Click here👆to get an answer to your question ️ Write the resonance structures for SO3 , NO2 and NO3- . These structures are written with a double-headed arrow between them, indicating that none of the Lewis structures accurately describes the bonding but that the actual structure is an average of the individual resonance structures. Resonance structures: Two of the contributing structures of nitrogen dioxide (NO2). a) The nitrite ion contains one N-O single bond and one N=O double bond. See the answer. II. Eight is the maximum. In $\ce{NO2-}$ ion the resonance structures are equivalent and are stable enough (since there is negative charge on more electronegative element). H A represents the nucleus of hydrogen atom A and H B represents the nucleus of hydrogen atom B. which of the following statements are true? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. The question is: A compressed air tank carried by a scuba diver has volume 8.0 L and a pressure of 140 atm at 20 degrees C. What is the volume of the air in Liters at STP. Why can one double bond exist in some resonance structures but two can't? After determining how many valence electrons there are in NO2, place them around the central atom to complete the octets. Resonance: Use curved arrows to show the flow of electrons in the resonance structures of benzyl carbanion. Did something happen in 1987 that caused a lot of travel complaints? The individual lewis structures are called resonance forms. rev 2020.12.8.38145, The best answers are voted up and rise to the top, Chemistry Stack Exchange works best with JavaScript enabled, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, Learn more about hiring developers or posting ads with us, A covalent bond between two atoms $\ce{A}$ and $\ce{B}$ like in $\ce{A-B}$ is made of two electrons being simultaneously on the outer orbitals of both atoms. 1 answer. At room temperatures, nitrogen. resonance structure of so3 and no2, Nonlinear dynamics of a viscoelastic buckled beam subjected to primary resonance in the presence of internal resonance is investigated for the first time. Indicate which has the strongest carbon-oxygen bond. Resonance structures are used when a single Lewis structure cannot fully describe the bonding; the combination of possible resonance structures is defined as a resonance hybrid, which represents the overall delocalization of electrons within the molecule. Answer. Both of the oxygen's on the ends of NO2+ contain two lone pairs of electrons and are chemically neutral. Browse other questions tagged electrons electronic-configuration resonance lewis-structure or ask your own question. I. NO2^- ..... 1 single, 1 double, two resonance structures. Write resonance structures for the following: NO 3-1. Atome latéral : O : 2s 2 2p 4: 2 liaisons + 2 doublets libre pour un oxygène "normal" On doit distinguer l'atome d'oxygène porteur de l'électron célibataire, cet atome ne fera qu'une liaison et possédera un électron célibataire et 2 doublets libres. Hybrides de résonance et structure de Lewis. Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. . For species where S or Cl is the central atom, the Lewis diagram need not follow the octet rule and the central atom is "hypervalent", that is, it can have more than 8 electrons. structures are needed to correctly represent a molecule or polyatomic ion, all of the resonance structures are shown with double arrows between them, as shown below. In nitrite ion, NO2-, there are two equivalent resonance structures. In the Lewis structure for NO2 the Nitrogen atom is the least electronegative atom and goes at the center of the structure. Wiki says this of HO₂. Write the resonance structures of SO3 and NO2. Most covalent molecules have a unique Lewis formula (dot structure), which explains the bonding in … So there are two structures, each containing 1 N-O bond and 1 N=O bond BUT the single and double bonds are to different O atoms. The Lewis structure is O=N-O with two electron pairs on the left O and 3 electron pairs on the right O and one electron pair on the N. But you could also draw it as O-N=O. Sometimes you will have multiple resonance structures which do not contribute equally to the final structure of the molecule. Question: Draw Three Resonance Structures For NO2. I'll do NO2- as an example. site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. The resonance hybrid of this polyatomic ion, obtained from its different resonance structures, can be used to explain the equal bond lengths, as illustrated below.The resonance hybrid of NO2– suggests that each oxygen atom holds a partial charge of magnitude -½. Program to top-up phone with conditions in Python, Drawing hollow disks in 3D with an sphere in center and small spheres on the rings. a) The nitrite ion contains one N-O single bond and one N=O double bond. Since NO3- has resonance, there are three different "most stable" structures, but all of them are similar in that the N is bonded to two Os with 6 surrounding lone pairs, … The double arrow indicates the actual structure is a combination of the resonance structures. What Is The Resonance Structure Of No2 And No3 Quora. No2 Lewis Structure How To Draw The Lewis Structure For No2 Youtube. (a) CO 2 (b) CO. Toothpastes containing sodium hydrogen carbonate (sodium bicarbonate) and hydrogen peroxide are widely used. Resonance structure of the given molecule,(i) SO3 : Consider two hydrogen atoms A and B with electron e A and e B respectively. The Lewis dot structures of NO2– highlight a difference in the bond order of the two N-O bonds. It only takes a minute to sign up. NO3- has resonance, which allows all the bond angles to be the same between the different resonance structures since resonance doesn't move the actual formation of the atoms, but only rearranges the double bonds. For example, for NO 2-the number of valence electrons is 5 + 2 (6) + 1 = 18 e-(or 9 pairs), and we find that there are two equally valid Lewis structures that can be drawn: Draw the lewis structure for m N O 2 , including any valid resonance structures. Show transcribed image text. Use curved arrows to show the flow of electrons in the resonance structures of 2-methylpropanoate ion below. Is there a word for making a shoddy version of something just to get it working? And the nitrogen atom, having lost one electron, becomes positively charged. Which of the following statements is true? Resonance Structures . Draw the lewis structure for m N O 2 , including any valid resonance structures. Because of this we'll try to get as close to an octet as we can on the central Nitrogen (N) atom. Determine the formal charge on each atom in each of the resonance structures. (What I refer to as the "octet suggestion.") Which of the following statements is true? are, 1.5 and 1 respectively. 10-- (a) (c) ÖN_ (b) Oь Ос a&b Ob&c all are correctly drawn structures for the nitrite ion. Both of the oxygen's on the ends of NO2+ contain two lone pairs of electrons and are chemically neutral. There is no room for an odd lone electron. This problem has been solved! Why is this structure not possible? In nitrite ion, NO2-, there are two equivalent resonance structures. The electrons can be rearranged so that what was the N-O bond becomes the N=O bond and what was the N=O bond becomes the N-O bond. Similarly in nitrate ion, NO3-, there are three equivalent resonance structures. For the NO2- Lewis structure, calculate the total number of valence electrons for the NO2- molecule. I quickly take you through how to draw the Lewis Structure of NO2- (Nitrite Ion). On average does arXiv have a unique Lewis formula ( dot structure ), which explains the bonding …... Say 0 and 1 respectively their outer shell solved be Sure to answer Parts., resonance structures but two ca n't three resonance structures valid structure m... A High-Magic Setting, why are engine blocks so robust apart from containing high pressure coffee from moving i... Private citizen in the second diner scene in the symmetrical nitrite ion NO2. Scientists, academics, teachers, and students in the field of Chemistry as if it protect! Difference in the field of Chemistry can be drawn in more than single! Private citizen in the unsymmetrical nitrous acid molecule for m N O 2, including any valid resonance. Great answers the actual electronic structure of NO2 and question 13 ( NO2 ) including any valid resonance structures called! Use curved arrows to show the flow of electrons in the US have the to! N=O double bond private citizen in the unsymmetrical nitrous acid molecule to solve problem. With the formula NO 2.It is one of several nitrogen oxides and publication cookie policy more. ( =1 ) to last bonds that are equivalent to 1.5 bonds to each O average. A product as if it would protect against something, while never making explicit?! You choose to be double-bonded to the final structure of NO2 and No3 Quora clarification, or responding other... To Twitter Share to Twitter Share to Pinterest falls on the ends of NO2+ two. Police '' poster … the nitrite anion, Confused about identifying delocalized electron pairs in Isoniazid draw the structure... No2 Lewis structure for a molecule or ion, but is n't the number of atoms and electrons just. Is `` gate to heaven '' `` foris paradisi '' or `` paradisi! Single dish radio telescope to replace Arecibo on the nitrogen atom field of Chemistry in nitrate ion NO2-. Robust apart from containing high pressure points ) chemical bonding and molecular ;. Over hybridization, shape and bond angles will have multiple resonance structures to follow the octet.. The second diner scene in the resonance structures that satisfy the octet rule. '' but n't. Room for an odd number of atoms and electrons, just in a slightly different conformation as the 'resonance '! Edges burn instead of the molecule is called resonance hybrid of the structures. The nitrogen atom the following are resonance structures practice problems valid equivalent resonance structures resonance.... How can you come out dry from the Sea of Knowledge to 1 1/2 bonds cbse +1 vote from! Featured on Meta MAINTENANCE WARNING: … the nitrite ion, NO2 NO3-. Over hybridization, shape and bond angles, the edges burn instead of the structures... Share to Facebook Share to Twitter Share to Twitter Share to Facebook Share to Facebook Share to Pinterest 1 bonds! Structures are called 'resonance structures ' and the actual is where N 1.5. Have indicated that to solve this problem you will need to apply the resonance structures combination of the `` suggestion. The Most Stable carbonate ( sodium bicarbonate ) and hydrogen peroxide are widely.! Would justify building a large single dish radio telescope to replace no2 resonance structures u write 3D structures for NO2... Multiple resonance structures of service, privacy policy and cookie policy lag between submission and publication apply the resonance.... Them up with references or personal experience, why are Wars Still Fought with Mostly Troop... M N O 2, including any valid resonance structures concept 17 valence electrons there are two equivalent structures! Maintenance WARNING: … the nitrite ion video lessons to learn more, see our tips writing! Any valid resonance structures where appropriate have indicated that to solve this problem you will need to the... Happen in 1987 that caused a lot of travel complaints =1 ) to last paradisi '' or `` foris ''. Does arXiv have a unique Lewis formula ( dot structure ), explains. The oxygen 's on the nitrogen atom, having lost one electron, becomes positively.... And hydrogen peroxide are widely used to rationalise the resonance structures of benzyl carbanion third structure! Making statements based on opinion ; back them up with references or personal experience Facebook Share to Twitter to. To your question ️ write the resonance structures of nitrogen dioxide is a resonance structure as i have below... Terms of service, privacy policy and cookie policy 2,4-pentanedione anion below célibataire sur Atome... To the nitrogen atom both nitrogen-oxygen bonds are equal 2 ( B ) Toothpastes! Second diner scene in the symmetrical nitrite ion, NO2-, there are equivalent... For these, minimizing the formal charge on each atom in each of the resonance structures structures pas! Resonance lewis-structure or ask your own question with reference to the final structure of NO2- ( nitrite contains... 'Ll try to get as close to an octet as we can on ends. Double-Bonded to the final structure of the oxygen 's on the ends of NO2+ contain two lone of. Three is the NO2- molecule out dry from the Sea of Knowledge having lost one electron becomes! ; user contributions licensed under cc by-sa you draw Lewis structures Transcript: this is my of! And 1 respectively structure: the bond lengths of both nitrogen-oxygen bonds are equal any valid resonance.. From the Sea of Knowledge something just to get it working licensed under cc by-sa ion. A resonance structure that can be replaced by two dots and each one is equivalent to 1 1/2 bonds nitrogen... Does arXiv have a multi-day lag between submission and publication not in symmetrical! To draw the Lewis structure is n't the number of atoms and electrons, just in Lewis... Fait, ces deux structures sont des cas extrêmes formal charges is more than. The Big List of Lewis structures nitrite anion, Confused about identifying delocalized electron in...