🔗 Bonding & Molecular Structure
104 chemistry topics in Bonding & Molecular Structure, from beginner to intermediate to advanced level. Each topic has a clear explanation, a worked example, frequently asked questions and an interactive lesson.
Beginner topics in Bonding & Molecular Structure (34)
- Chemical BondAn attractive force holding atoms together in molecules, crystals or other stable…
- Octet RuleAtoms tend to gain, lose or share electrons to reach eight valence electrons like a noble…
- Duet RuleHydrogen and helium are stable with two electrons in their outermost shell.
- Ionic BondElectrostatic attraction between oppositely charged ions formed by electron transfer,…
- Covalent BondA bond formed by sharing electron pairs between two atoms, typically nonmetals.
- Metallic BondAttraction between positive metal ions and a sea of delocalized electrons.
- Lewis Dot SymbolsDiagrams that show valence electrons as dots around an element's symbol.
- Lewis StructuresDiagrams showing bonding and lone pairs of electrons in molecules and ions.
- Single Double and Triple BondsAtoms share one, two or three electron pairs; more bonds mean shorter and stronger links.
- Lone PairsPairs of valence electrons not involved in bonding that occupy space around an atom.
- Bond LengthThe average distance between nuclei of two bonded atoms.
- Bond EnergyThe energy needed to break one mole of a particular bond in the gas phase.
- Bond PolarityUnequal sharing of electrons due to electronegativity difference creates partial charges.
- Polar and Nonpolar MoleculesMolecules with net dipole moment are polar; symmetrical ones with canceling dipoles are…
- Properties of Ionic CompoundsHigh melting points, brittle crystals, and conduction when molten or dissolved.
- Properties of Covalent CompoundsGenerally lower melting points and poor electrical conductivity, with strong bonds within…
- Properties of MetalsMalleability, ductility, luster and electrical conductivity arise from the electron sea.
- VSEPR TheoryElectron groups around a central atom repel one another and arrange to minimize…
- Molecular GeometryThe three-dimensional arrangement of atoms only, ignoring lone pairs.
- Linear GeometryTwo electron groups arranged at 180 degrees, as in CO2 and BeCl2.
- Trigonal Planar GeometryThree groups at 120 degrees in a plane, as in BF3.
- Tetrahedral GeometryFour groups at 109.5 degrees, as in methane.
- Bent GeometryAngular shape caused by lone pairs, as in water and SO2.
- Trigonal Pyramidal GeometryThree bonds and one lone pair on the central atom, as in ammonia.
- Sigma BondA bond formed by head-on overlap of orbitals along the internuclear axis.
- Pi BondA bond formed by sideways overlap of p orbitals above and below the bond axis.
- Intermolecular ForcesAttractions between molecules that are weaker than bonds and control physical properties.
- London Dispersion ForcesWeak attractions from temporary dipoles in all molecules, increasing with molar mass and…
- Dipole-Dipole ForcesAttractions between permanent dipoles in polar molecules.
- Hydrogen BondingA strong dipole attraction between H bonded to N, O or F and a lone pair on another N, O…
- Boiling Point and Intermolecular ForcesStronger intermolecular forces lead to higher boiling and melting points.
- Molecular SolidsDiscrete molecules held by intermolecular forces, giving soft low-melting solids such as…
- Ionic SolidsIons arranged in a lattice, such as NaCl, with high melting points and brittleness.
- Metallic SolidsMetal cations in a lattice with delocalized electrons, giving conductivity and…
Intermediate topics in Bonding & Molecular Structure (40)
- Formal ChargeThe charge an atom would have if bonding electrons were shared equally; helps pick the…
- ResonanceWhen one Lewis structure is inadequate, the real molecule is a hybrid of several…
- Resonance HybridThe actual delocalized electronic structure, an average of the contributing resonance…
- Expanded OctetElements in period 3 and beyond may hold more than eight valence electrons, as in SF6 and…
- Incomplete OctetSome compounds such as BF3 have central atoms with fewer than eight electrons.
- Odd-Electron MoleculesFree radicals such as NO and NO2 contain an unpaired electron and are often reactive.
- Coordinate BondA covalent bond where both shared electrons come from the same atom, as in NH4+.
- Bond OrderThe number of bonding electron pairs between two atoms; higher order means shorter…
- Dipole MomentA measure of charge separation equal to charge times distance, measured in debye.
- Percent Ionic CharacterThe degree to which a bond behaves as ionic, estimated from the dipole moment or…
- PolarizabilityHow easily an electron cloud is distorted by an electric field; it increases with atomic…
- Lattice EnergyThe energy released when gaseous ions form one mole of ionic solid.
- SemiconductorsMaterials with a small band gap, such as silicon, whose conductivity rises with…
- DopingAdding trace impurities to a semiconductor to create n-type or p-type conductivity.
- Electron Domain GeometryThe arrangement of all bonding and lone-pair regions around a central atom.
- Trigonal Bipyramidal GeometryFive groups with axial and equatorial positions, as in PCl5.
- Octahedral GeometrySix groups at 90 degrees, as in SF6.
- Bond Angle DeviationsLone pairs repel more strongly than bonding pairs, compressing angles such as 104.5…
- Valence Bond TheoryCovalent bonds form by overlap of half-filled atomic orbitals sharing a pair of electrons.
- HybridizationMixing of atomic orbitals to create equivalent hybrid orbitals that explain molecular…
- sp3 HybridizationOne s and three p orbitals mix to form four tetrahedral hybrids, as in methane.
- sp2 HybridizationOne s and two p orbitals form three planar hybrids at 120 degrees, as in ethene.
- sp HybridizationOne s and one p orbital form two linear hybrids, as in ethyne.
- Hybridization of Water and AmmoniaBoth oxygen and nitrogen are sp3 hybridized with lone pairs occupying hybrid orbitals.
- DiamagnetismProperty of substances with all electrons paired that are weakly repelled by magnetic…
- ParamagnetismProperty of substances with unpaired electrons that are attracted into magnetic fields.
- DelocalizationElectrons spread across several atoms, as in benzene, lowering energy and adding…
- Benzene BondingSix pi electrons delocalize above and below a planar sp2 ring, giving equal carbon-carbon…
- Ion-Dipole ForcesAttractions between ions and polar molecules, important in dissolving salts in water.
- Dipole-Induced Dipole ForcesA permanent dipole distorts a nonpolar molecule's electron cloud, creating attraction.
- Water's Anomalous PropertiesHydrogen bonding gives water high boiling point, high heat capacity and lower-density ice.
- Covalent Network SolidsAtoms linked by covalent bonds throughout, such as diamond and quartz, give extreme…
- Allotropes of CarbonDiamond, graphite, graphene, fullerenes and nanotubes are different structural forms of…
- Graphite StructureLayers of sp2 carbon hexagons with delocalized electrons make it a soft electrical…
- Diamond StructureEach carbon is sp3 bonded to four others in a rigid tetrahedral network.
- Coordination CompoundsComplexes in which a central metal ion is bound to ligands through coordinate bonds.
- LigandsIons or molecules that donate electron pairs to a central metal ion.
- Coordination NumberThe number of donor atoms directly bonded to the central metal ion.
- Van der Waals RadiusHalf the closest distance between nonbonded atoms of neighbouring molecules.
- Covalent RadiusHalf the bond length between two identical bonded atoms.
Advanced topics in Bonding & Molecular Structure (30)
- Fajans' RulesCovalent character in ionic bonds increases with small highly charged cations and large…
- Born-Haber CycleA thermochemical cycle using Hess's law to calculate lattice energy from measurable…
- Band TheoryIn solids, atomic orbitals merge into energy bands; gaps between bands determine…
- See-Saw GeometryFour bonds and one lone pair in a trigonal bipyramid, as in SF4.
- T-Shaped GeometryThree bonds and two lone pairs on a trigonal bipyramid, as in ClF3.
- Square Planar GeometryFour bonds and two lone pairs in an octahedral arrangement, as in XeF4.
- Square Pyramidal GeometryFive bonds and one lone pair on an octahedral base, as in BrF5.
- sp3d and sp3d2 HybridizationExpanded valence shell hybridization for five and six electron groups, as in PCl5 and SF6.
- Molecular Orbital TheoryAtomic orbitals combine into delocalized molecular orbitals spanning the whole molecule.
- Bonding Molecular OrbitalA lower-energy combination of atomic orbitals that concentrates electron density between…
- Antibonding Molecular OrbitalA higher-energy combination with a node between nuclei that weakens bonding when occupied.
- MO Diagram of Homonuclear DiatomicsEnergy ordering of molecular orbitals used to derive bond order and magnetism of…
- Paramagnetism of OxygenMO theory shows O2 has two unpaired electrons in degenerate pi-star orbitals, making it…
- Heteronuclear Diatomic MOsIn molecules like CO, orbital energies are unequal so bonding orbitals resemble the more…
- Aromaticity and Huckel's RulePlanar cyclic conjugated rings with 4n+2 pi electrons are especially stable.
- Intramolecular Hydrogen BondingHydrogen bonds within one molecule, such as in o-nitrophenol, lower its boiling point.
- GrapheneA single atom-thick sheet of sp2 carbon with exceptional strength and conductivity.
- FullerenesHollow carbon cages such as C60 buckminsterfullerene made of pentagons and hexagons.
- ChelationBinding of a polydentate ligand to a metal through multiple donor atoms, forming stable…
- Crystal Field TheoryExplains d orbital splitting in metal complexes due to electrostatic repulsion from…
- Spectrochemical SeriesAn ordering of ligands by the crystal-field splitting they cause.
- High Spin and Low Spin ComplexesWeak-field ligands leave electrons unpaired while strong-field ligands cause pairing in…
- Color of Transition Metal ComplexesColors arise from d-d electronic transitions absorbing visible light.
- Isomerism in ComplexesComplexes show structural isomerism and stereoisomerism including geometric and optical…
- Hydrogen Molecule IonH2+ is the simplest molecule, a one-electron system explained by molecular orbital theory.
- HypervalencyMolecules with central atoms seemingly exceeding eight electrons, often better described…
- Three-Center Two-Electron BondA bond in which two electrons bind three atoms, as in diborane.
- Banana BondsBent bonds in strained molecules where overlap is off the internuclear line.
- Electron-Pair Repulsion RankingLone pair-lone pair repulsion exceeds lone pair-bond pair, which exceeds bond pair-bond…
- Bent's RuleMore electronegative substituents prefer hybrid orbitals with more p character.
Frequently asked questions about Bonding & Molecular Structure
How many topics are in Bonding & Molecular Structure?
Bonding & Molecular Structure has 104 topics, from beginner to intermediate to advanced level.
Where should I start in Bonding & Molecular Structure?
Start with Chemical Bond at the beginner level, then work through the topics in order.
Does every topic have an explanation and an example?
Yes. Each topic page has an in-depth explanation, a worked example, FAQs and links to related topics.