It turns out that if your octet is filled with all these atoms, the way you determine the one that's most stable is by figuring out what row that atom is in. It turns out that for each of the second row elements, the element is going to prefer to own or it's going to prefer to have a valence determined by its group number. So what that means is that if an atom is in group 4, like carbon, then how many valence electrons is it going to want to have? 4. So this is going to be the most stable arrangement of carbon by far, whereas all these other ones are going to get progressively worse and worse. In fact, some of these don't even exist because they would be so crazy hard to create. They'd be so unstable. Does that make sense? So now what I want to do is extend this because you're like oh, well, Johnny, everyone knows carbon has 4 bonds. Maybe you learned that in gen chem. But now I want to extend this to all the other atoms so that you guys will know for the second row what they look like and what they're always going to want to look like in their neutral bonding preference. All right. So let's go through this really quick. As you can see, I've listed different atoms kind of in order of where they are in the periodic table and we're just going to go ahead and start off with hydrogen. Now I understand that hydrogen is not in the 2nd row, but it's way more common than lithium, so we're going to just work with hydrogen. We're going to replace that one. Hydrogen is in group 1a and that means that how many electrons does it want to have in its octet? Do you guys remember? 2. So that means that how can an atom have an octet? Well, it can either have lone pairs or it can have bonds. So that means the hydrogen can exist in 2 different forms. I could have a hydrogen that has a bond. That would give it its 2 electrons. It would fill an octet, but I could also have a hydrogen that has a lone pair. Do you guys see that? Would both of these fulfill the octet? Yes. They would both fulfill the octet. So now my question is, are both of these equally stable? The way that I find that out is I look at the group number. Well, what's the group number? 1. So how many valence electrons does the first hydrogen have? It has one because I only count one for each stick. The second one, how many does it have? 2. So which one is going to be the most stable? This is going to be the way that hydrogen looks. It will not look like this. That's why every time you see hydrogen, it's always attached with just one stick, with one bond because that's going to be the one that satisfies not only the octet but also the valence of having one stick or one valence electron. Does that make sense? Cool. So now what I want you guys to do down here, now that we've figured that out, is really just write what we have. Like let's write our results. How many bonds does hydrogen like to have? 1. How many lone pairs does it like to have? 0. You guys cool with that? Let's move on. So now let's go to beryllium. So beryllium, do you guys remember how many octet electrons beryllium likes to have? Four. All right. It likes to have 4. So there's going to be actually 3 different ways that we could do this. I'll draw all 3 just so that you guys can kind of realize what that is. We could have beryllium with 2 sticks. We could have beryllium with a stick and a lone pair. Or we could have beryllium with 2 lone pairs. Are you guys getting that? All of these versions would satisfy the octet rule equally. But the way I determine the ones that's most stable is I look at the group number. What's the group number? 2. If I'm in group 2, which of these is going to be the favored arrangement? You guys got it. It's beryllium with the 2 sticks. Because that's the only one that is going to not only fulfill the octet but also fulfill the valence. So that means that beryllium in its bonding preference likes to have how many bonds? How many lone pairs? 0. Okay. So hopefully, that's making sense. Let's move on to the next one. All right. So now we are at boron. Do you guys remember how many electrons, octet electrons boron likes to have? This is from your octet rule. I think we talked about it. 6. How many valence electrons does it like to have? 3. So can you guys predict what I'm going to want to do here? I think I heard it. What you're going to want is boron with 3 bonds. The reason is because that's not only going to fulfill your octet of 6, but it's also going to fulfill your valence of 3. Cool? So that means that now it's going to want to have 3 bonds and 0 lone pairs. Are you guys kind of seeing a pattern here? None of these want lone pairs and they're escalating. So we already got to carbon and just by looking at this pattern, what should the next number be? Well, it should be that I have 4 bonds and 0 lone pairs. And when you draw it out, it actually does come out to that. This carbon wants to have 8 electrons. Remember that carbon, nitrogen, oxygen, and fluorine all want to have 8. So they're all going to stay at 8 and it wants to have 4 valence electrons because it's in group 4. So that actually is the arrangement. So now, let's continue to apply wants to have It wants to have 8. If we were just to apply this pattern, don't draw this yet, but I'm just showing you, what I would do is I would draw a 5 here and a 0 here and I would say nitrogen wants to have 5 bonds and 0 lone pairs. Is there a problem with that? Am I making a mistake? I'm actually making a huge mistake. The reason is that if nitrogen had 5 bonds, would it still satisfy the octet rule? No because remember, each bond counts as 2. So if nitrogen had 5 bonds, it would have 10 electrons and it would break the octet rule and it would be even worse off. It would be super unstable. So that means that somehow I need to get nitrogen to have 5 valence electrons, but still only 8 octet electrons. So that means that out of these electrons, out of these 8 electrons, I need to get nitrogen to own more of the electrons. How can we get it to own more? By adding lone pairs. Hopefully, what you guys maybe came to on your own is that nitrogen, what I'm going to want to do is 3 bonds and one lone pair. Because if I can do that, then what I'm going to get is I have 8 electrons total. 8. And then I have every stick counts as 1. 1, 2, 3. And every dot counts as 1. 4, 5. So now when I go down to my pattern, it's actually going to be that I want 3 bonds and one lone pair. Now this is going to start a new pattern. So for oxygen, oxygen still wants 8 electrons, but now it wants to own 6 of them. It wants even more because it's in group 6. So can you guys think of an arrangement that would work for that? Yeah, you guys are smart. You guys know what's going on now. So it would be 2 bonds and 2 lone pairs. Because now the more lone pairs I have, the more I'm owning. So that means that now this would count as 6 valence electrons, 8 octet, so this would be 2 bonds and 2 lone pairs. You guys can see the pattern here. We can guess what the last one's going to be and that pattern actually does hold. Fluorine would want to have you can see the bonds keep decreasing, so fluorine would have one bond and it would have 3 lone pairs. That actually makes sense because if you give fluorine one bond and 3 lone pairs, what you get is an octet of 8, but a valence of 7. Now guys, I really can't emphasize the value of understanding this enough because these bonding preferences are what a bunch of other topics are built off of. For example, bond line structures, formal charges, all this stuff has to do with your knowledge of being able to know these preferences. Also, it's just going to help you draw compounds later.
Table of contents
- 1. A Review of General Chemistry5h 5m
- Summary23m
- Intro to Organic Chemistry5m
- Atomic Structure16m
- Wave Function9m
- Molecular Orbitals17m
- Sigma and Pi Bonds9m
- Octet Rule12m
- Bonding Preferences12m
- Formal Charges6m
- Skeletal Structure14m
- Lewis Structure20m
- Condensed Structural Formula15m
- Degrees of Unsaturation15m
- Constitutional Isomers14m
- Resonance Structures46m
- Hybridization23m
- Molecular Geometry16m
- Electronegativity22m
- 2. Molecular Representations1h 14m
- 3. Acids and Bases2h 46m
- 4. Alkanes and Cycloalkanes4h 19m
- IUPAC Naming29m
- Alkyl Groups13m
- Naming Cycloalkanes10m
- Naming Bicyclic Compounds10m
- Naming Alkyl Halides7m
- Naming Alkenes3m
- Naming Alcohols8m
- Naming Amines15m
- Cis vs Trans21m
- Conformational Isomers13m
- Newman Projections14m
- Drawing Newman Projections16m
- Barrier To Rotation7m
- Ring Strain8m
- Axial vs Equatorial7m
- Cis vs Trans Conformations4m
- Equatorial Preference14m
- Chair Flip9m
- Calculating Energy Difference Between Chair Conformations17m
- A-Values17m
- Decalin7m
- 5. Chirality3h 39m
- Constitutional Isomers vs. Stereoisomers9m
- Chirality12m
- Test 1:Plane of Symmetry7m
- Test 2:Stereocenter Test17m
- R and S Configuration43m
- Enantiomers vs. Diastereomers13m
- Atropisomers9m
- Meso Compound12m
- Test 3:Disubstituted Cycloalkanes13m
- What is the Relationship Between Isomers?16m
- Fischer Projection10m
- R and S of Fischer Projections7m
- Optical Activity5m
- Enantiomeric Excess20m
- Calculations with Enantiomeric Percentages11m
- Non-Carbon Chiral Centers8m
- 6. Thermodynamics and Kinetics1h 22m
- 7. Substitution Reactions1h 48m
- 8. Elimination Reactions2h 30m
- 9. Alkenes and Alkynes2h 9m
- 10. Addition Reactions3h 18m
- Addition Reaction6m
- Markovnikov5m
- Hydrohalogenation6m
- Acid-Catalyzed Hydration17m
- Oxymercuration15m
- Hydroboration26m
- Hydrogenation6m
- Halogenation6m
- Halohydrin12m
- Carbene12m
- Epoxidation8m
- Epoxide Reactions9m
- Dihydroxylation8m
- Ozonolysis7m
- Ozonolysis Full Mechanism24m
- Oxidative Cleavage3m
- Alkyne Oxidative Cleavage6m
- Alkyne Hydrohalogenation3m
- Alkyne Halogenation2m
- Alkyne Hydration6m
- Alkyne Hydroboration2m
- 11. Radical Reactions1h 58m
- 12. Alcohols, Ethers, Epoxides and Thiols2h 42m
- Alcohol Nomenclature4m
- Naming Ethers6m
- Naming Epoxides18m
- Naming Thiols11m
- Alcohol Synthesis7m
- Leaving Group Conversions - Using HX11m
- Leaving Group Conversions - SOCl2 and PBr313m
- Leaving Group Conversions - Sulfonyl Chlorides7m
- Leaving Group Conversions Summary4m
- Williamson Ether Synthesis3m
- Making Ethers - Alkoxymercuration4m
- Making Ethers - Alcohol Condensation4m
- Making Ethers - Acid-Catalyzed Alkoxylation4m
- Making Ethers - Cumulative Practice10m
- Ether Cleavage8m
- Alcohol Protecting Groups3m
- t-Butyl Ether Protecting Groups5m
- Silyl Ether Protecting Groups10m
- Sharpless Epoxidation9m
- Thiol Reactions6m
- Sulfide Oxidation4m
- 13. Alcohols and Carbonyl Compounds2h 17m
- 14. Synthetic Techniques1h 26m
- 15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
- Purpose of Analytical Techniques5m
- Infrared Spectroscopy16m
- Infrared Spectroscopy Table31m
- IR Spect:Drawing Spectra40m
- IR Spect:Extra Practice26m
- NMR Spectroscopy10m
- 1H NMR:Number of Signals26m
- 1H NMR:Q-Test26m
- 1H NMR:E/Z Diastereoisomerism8m
- H NMR Table24m
- 1H NMR:Spin-Splitting (N + 1) Rule22m
- 1H NMR:Spin-Splitting Simple Tree Diagrams11m
- 1H NMR:Spin-Splitting Complex Tree Diagrams12m
- 1H NMR:Spin-Splitting Patterns8m
- NMR Integration18m
- NMR Practice14m
- Carbon NMR4m
- Structure Determination without Mass Spect47m
- Mass Spectrometry12m
- Mass Spect:Fragmentation28m
- Mass Spect:Isotopes27m
- 16. Conjugated Systems6h 13m
- Conjugation Chemistry13m
- Stability of Conjugated Intermediates4m
- Allylic Halogenation12m
- Reactions at the Allylic Position39m
- Conjugated Hydrohalogenation (1,2 vs 1,4 addition)26m
- Diels-Alder Reaction9m
- Diels-Alder Forming Bridged Products11m
- Diels-Alder Retrosynthesis8m
- Molecular Orbital Theory9m
- Drawing Atomic Orbitals6m
- Drawing Molecular Orbitals17m
- HOMO LUMO4m
- Orbital Diagram:3-atoms- Allylic Ions13m
- Orbital Diagram:4-atoms- 1,3-butadiene11m
- Orbital Diagram:5-atoms- Allylic Ions10m
- Orbital Diagram:6-atoms- 1,3,5-hexatriene13m
- Orbital Diagram:Excited States4m
- Pericyclic Reaction10m
- Thermal Cycloaddition Reactions26m
- Photochemical Cycloaddition Reactions26m
- Thermal Electrocyclic Reactions14m
- Photochemical Electrocyclic Reactions10m
- Cumulative Electrocyclic Problems25m
- Sigmatropic Rearrangement17m
- Cope Rearrangement9m
- Claisen Rearrangement15m
- 17. Ultraviolet Spectroscopy51m
- 18. Aromaticity2h 34m
- 19. Reactions of Aromatics: EAS and Beyond5h 1m
- Electrophilic Aromatic Substitution9m
- Benzene Reactions11m
- EAS:Halogenation Mechanism6m
- EAS:Nitration Mechanism9m
- EAS:Friedel-Crafts Alkylation Mechanism6m
- EAS:Friedel-Crafts Acylation Mechanism5m
- EAS:Any Carbocation Mechanism7m
- Electron Withdrawing Groups22m
- EAS:Ortho vs. Para Positions4m
- Acylation of Aniline9m
- Limitations of Friedel-Crafts Alkyation19m
- Advantages of Friedel-Crafts Acylation6m
- Blocking Groups - Sulfonic Acid12m
- EAS:Synergistic and Competitive Groups13m
- Side-Chain Halogenation6m
- Side-Chain Oxidation4m
- Reactions at Benzylic Positions31m
- Birch Reduction10m
- EAS:Sequence Groups4m
- EAS:Retrosynthesis29m
- Diazo Replacement Reactions6m
- Diazo Sequence Groups5m
- Diazo Retrosynthesis13m
- Nucleophilic Aromatic Substitution28m
- Benzyne16m
- 20. Phenols55m
- 21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
- Naming Aldehydes8m
- Naming Ketones7m
- Oxidizing and Reducing Agents9m
- Oxidation of Alcohols28m
- Ozonolysis7m
- DIBAL5m
- Alkyne Hydration9m
- Nucleophilic Addition8m
- Cyanohydrin11m
- Organometallics on Ketones19m
- Overview of Nucleophilic Addition of Solvents13m
- Hydrates6m
- Hemiacetal9m
- Acetal12m
- Acetal Protecting Group16m
- Thioacetal6m
- Imine vs Enamine15m
- Addition of Amine Derivatives5m
- Wolff Kishner Reduction7m
- Baeyer-Villiger Oxidation39m
- Acid Chloride to Ketone7m
- Nitrile to Ketone9m
- Wittig Reaction18m
- Ketone and Aldehyde Synthesis Reactions14m
- 22. Carboxylic Acid Derivatives: NAS2h 51m
- Carboxylic Acid Derivatives7m
- Naming Carboxylic Acids9m
- Diacid Nomenclature6m
- Naming Esters5m
- Naming Nitriles3m
- Acid Chloride Nomenclature5m
- Naming Anhydrides7m
- Naming Amides5m
- Nucleophilic Acyl Substitution18m
- Carboxylic Acid to Acid Chloride6m
- Fischer Esterification5m
- Acid-Catalyzed Ester Hydrolysis4m
- Saponification3m
- Transesterification5m
- Lactones, Lactams and Cyclization Reactions10m
- Carboxylation5m
- Decarboxylation Mechanism14m
- Review of Nitriles46m
- 23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
- 24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
- Tautomerization9m
- Tautomers of Dicarbonyl Compounds6m
- Enolate4m
- Acid-Catalyzed Alpha-Halogentation4m
- Base-Catalyzed Alpha-Halogentation3m
- Haloform Reaction8m
- Hell-Volhard-Zelinski Reaction3m
- Overview of Alpha-Alkylations and Acylations5m
- Enolate Alkylation and Acylation12m
- Enamine Alkylation and Acylation16m
- Beta-Dicarbonyl Synthesis Pathway7m
- Acetoacetic Ester Synthesis13m
- Malonic Ester Synthesis15m
- 25. Condensation Chemistry2h 9m
- 26. Amines1h 43m
- 27. Heterocycles2h 0m
- Nomenclature of Heterocycles15m
- Acid-Base Properties of Nitrogen Heterocycles10m
- Reactions of Pyrrole, Furan, and Thiophene13m
- Directing Effects in Substituted Pyrroles, Furans, and Thiophenes16m
- Addition Reactions of Furan8m
- EAS Reactions of Pyridine17m
- SNAr Reactions of Pyridine18m
- Side-Chain Reactions of Substituted Pyridines20m
- 28. Carbohydrates5h 53m
- Monosaccharide20m
- Monosaccharides - D and L Isomerism9m
- Monosaccharides - Drawing Fischer Projections18m
- Monosaccharides - Common Structures6m
- Monosaccharides - Forming Cyclic Hemiacetals12m
- Monosaccharides - Cyclization18m
- Monosaccharides - Haworth Projections13m
- Mutarotation11m
- Epimerization9m
- Monosaccharides - Aldose-Ketose Rearrangement8m
- Monosaccharides - Alkylation10m
- Monosaccharides - Acylation7m
- Glycoside6m
- Monosaccharides - N-Glycosides18m
- Monosaccharides - Reduction (Alditols)12m
- Monosaccharides - Weak Oxidation (Aldonic Acid)7m
- Reducing Sugars23m
- Monosaccharides - Strong Oxidation (Aldaric Acid)11m
- Monosaccharides - Oxidative Cleavage27m
- Monosaccharides - Osazones10m
- Monosaccharides - Kiliani-Fischer23m
- Monosaccharides - Wohl Degradation12m
- Monosaccharides - Ruff Degradation12m
- Disaccharide30m
- Polysaccharide11m
- 29. Amino Acids3h 20m
- Proteins and Amino Acids19m
- L and D Amino Acids14m
- Polar Amino Acids14m
- Amino Acid Chart18m
- Acid-Base Properties of Amino Acids33m
- Isoelectric Point14m
- Amino Acid Synthesis: HVZ Method12m
- Synthesis of Amino Acids: Acetamidomalonic Ester Synthesis16m
- Synthesis of Amino Acids: N-Phthalimidomalonic Ester Synthesis13m
- Synthesis of Amino Acids: Strecker Synthesis13m
- Reactions of Amino Acids: Esterification7m
- Reactions of Amino Acids: Acylation3m
- Reactions of Amino Acids: Hydrogenolysis6m
- Reactions of Amino Acids: Ninhydrin Test11m
- 30. Peptides and Proteins2h 42m
- Peptides12m
- Primary Protein Structure4m
- Secondary Protein Structure17m
- Tertiary Protein Structure11m
- Disulfide Bonds17m
- Quaternary Protein Structure10m
- Summary of Protein Structure7m
- Intro to Peptide Sequencing2m
- Peptide Sequencing: Partial Hydrolysis25m
- Peptide Sequencing: Partial Hydrolysis with Cyanogen Bromide7m
- Peptide Sequencing: Edman Degradation28m
- Merrifield Solid-Phase Peptide Synthesis18m
- 31. Catalysis in Organic Reactions1h 30m
- 32. Lipids 2h 50m
- 33. The Organic Chemistry of Metabolic Pathways2h 52m
- Intro to Metabolism6m
- ATP and Energy6m
- Intro to Coenzymes3m
- Coenzymes in Metabolism16m
- Energy Production in Biochemical Pathways5m
- Intro to Glycolysis3m
- Catabolism of Carbohydrates: Glycolysis27m
- Glycolysis Summary15m
- Pyruvate Oxidation (Simplified)4m
- Anaerobic Respiration11m
- Catabolism of Fats: Glycerol Metabolism11m
- Intro to Citric Acid Cycle7m
- Structures of the Citric Acid Cycle19m
- The Citric Acid Cycle35m
- 34. Nucleic Acids1h 32m
- 35. Transition Metals6h 14m
- Electron Configuration of Elements45m
- Coordination Complexes20m
- Ligands24m
- Electron Counting10m
- The 18 and 16 Electron Rule13m
- Cross-Coupling General Reactions40m
- Heck Reaction40m
- Stille Reaction13m
- Suzuki Reaction25m
- Sonogashira Coupling Reaction17m
- Fukuyama Coupling Reaction15m
- Kumada Coupling Reaction13m
- Negishi Coupling Reaction16m
- Buchwald-Hartwig Amination Reaction19m
- Eglinton Reaction17m
- Catalytic Allylic Alkylation18m
- Alkene Metathesis23m
- 36. Synthetic Polymers1h 49m
- Introduction to Polymers6m
- Chain-Growth Polymers10m
- Radical Polymerization15m
- Cationic Polymerization8m
- Anionic Polymerization8m
- Polymer Stereochemistry3m
- Ziegler-Natta Polymerization4m
- Copolymers6m
- Step-Growth Polymers11m
- Step-Growth Polymers: Urethane6m
- Step-Growth Polymers: Polyurethane Mechanism10m
- Step-Growth Polymers: Epoxy Resin8m
- Polymers Structure and Properties8m
1. A Review of General Chemistry
Bonding Preferences
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Bonding Preferences practice set
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